Market Garden was a high risk operation but judging an entire career for just one operation is easy , I can do the same for Patton (had entire Task Force and POWs destroyed to save his son in law a few weeks before end of war) , Bradley (suffered twice as many casaulties in Hurtgen Forest for no advance) , Hodges (Hurtgen Forest then , caught suprised and lost control at Battle of Bulge , leaving 8.000 men to be captured at Schnee Eiffel alone) , Halsey (Battle of Leyte Gulf antics of getting entire Third Fleet after Japanese decoy and then putting his fleet in the path of a typhoon later) and Auchinleck (let both Tobruk and Mersa Matruh captured with 40.000 prisoners and vast supply depot captured by enemy) etc
Market Garden was only sensetionalised because of Hollywood history with United Artist movie production that was designed to humiliate British military effort in 1970’ies when US Army public credits in comparison was low but was designed to be increased with DoD funding after Vietnam War. (Hurtgen Forest , Lorreine Campaign or Schnee Eiffel did not get a Hollywood treatment) And no Montgomery did NOT have ULTRA intelligence. Read John Buckley’s “Operation Market Garden” : The ULTRA intelligence and air recon information was sent directly to 1st Airborne Army HQ in England that was tasked with planning of airborne drops but its commanders (Browning , Brereton and Leigh Malory ) ignored it within seven days of hasty planning constraint because SS Panzer units in the Oosterbeek were indeed in low strength (they had only few tanks and in total 8.000 men dispersed over Netherlands) but German ability of reorganisation and creating temporary battlegroup formations in emergencies was ignored by Browning and Brereton.
After giving strategic orders to 1st Airborne Army on 9th September , Montgomery was in Belgium , leading the operations of 21st Army Group in Northwest Europe. He had nothing to do with operational or tactical preperation or planning of airborne drops. ULTRA information about location of 2nd SS Panzer Corps reached only on 16th September to 21st Army Group HQ , too late to halt the momentum of operation. He ordered “do your best planning” to Browning , Brereton , Taylor , Gavin , Urqhuart and Leigh Mallory on 9th September and all of them dropped the ball. Gavin , overracting to the news of 1.000 (non existent) panzers awaiting in Reichswald forests , neglected to capture Nijmegen bridge on first moments of landing with a Coup de Main landing instead reinforced Groesbeek heights. Urqhuart bowed to the pressure of RAF Chiefs Lewis Brereton , Arthur Teddler and Leigh Mallory to transport 1st Airborne Divison to Arnhem in three different airborne drops for three days instead of one single drop to maximise the suprise and speed advantage (due to lack of transport aircraft excuse RAF and USAAF chiefs objected one single drop and got away with it , the paratroopers paid the price) On top of that entire 1st Airborne Division landed 15 km away from main target , Arnhem bridge , forfeiting any suprise or speed advantage due to RAF chiefs Arthur Teddler and Leigh Mallory’s pressure to stay away from German anti aircraft zones and minimise pilot and aircraft losses (again paratroopers paid the price) , not to mention 1st Airborne Division was issued with malfunctioning radios.
Montgomery had nothing to do with these operational blunders of 1st Airborne Army in England , only after post war revisionism (after Monty’s death to villify him with aid of Hollywood) he was declared responsible while Browning (who became liason officer in Buckingham Palace after the war , who had used 30 idle gliders to transport his entire HQ to Nijmegen and not sparing one to capture Nijmegen or Arnhem bridge on first hours of landing with a coup de main operation when the example of sucess in Pegasus Bridge was plain to see in coup de main suprise operations) , Lewis Brereton (same US Army Air Force general who let MacArthur’s airforce and B-17 bombers destroyed in Phillippines in 8th December 1941 and got promoted after that) were forgotten and Urqhuart (due to played by Sean Connery in the movie) lionised when in actuality he was an infantry general not airborne officer and should not be commanding an airborne unit. Teddler and Leigh Mallory being RAF officers and enemies of Montgomery twisted the whole history and buried their own responsibility in the resulting failure.
despite continuing to ignore the critical value of the port of Antwerp, which he had been put in charge of taking and clearing the waterway of. This was not completed until November 28th, 10 weeks after Market-Garden. If he had done what he should have (what he had been repeatedly ordered to
Again falsified revisionist history from Cornelius Ryan era. Capture of Scheldt and opening of Antwerp was NOT ordered by SHEAF (Eisenhower , Bedell Smith) to 21st Army Group till end of September because as General Horrocks 30th Corps commander admitted everyone was fixated on Rhine , crossing the Rhine and ending the war quickly once it was crossed in f September. One could blame Montgomery of neglecting Antwerp approaches (which was fortified by 90.000 or so German troops from 15th German Army that had Hitler orders to hold it to the last to deny Antwerp opening so it would be a long delay to first ships to pass through Scheldt till German batteries in Walcharen silenced and minefields were cleared anyway regardless of cutting Scheldt peninsula from east when Germans had route retreat from north anyway and pulled most of the 15th Army from Scheldt in first three weeks of September) but he is not alone on that mistake. Eisenhower’s decison for a broad front on advancing German frontier also played havoc on supply issues.
As for 30th Corps and Irish Guards , you know they advanced 300 miles in less than a week from Normandy to Antwerp in seven days in August - September 1944. The nature of the terrain (lowlands with mudddy terrain) and single highway was not their fault and after first day of their advance on 17th September , getting through German ambush they advanced from Neerpelt to Grave and Nijmegen in two days (52 miles) in three days (17-19 September) despite 101st US Airborne Division failed to capture Son bridge (which was blown to their faces) at Wilhelmina Channel when its general Maxwell Taylor also neglected coup de main operation and capturing the bridge at first moments of landings (Taylor became Chief of Staff of US Army and ambassador to Vietnam and on of the first and most passinate advocates of US involvement in Vietnam in 1950-60 era) , they had to put a pontoon bridge and wait for 18 hours for that. If Browning and Gavin had not neglected to capture Nijmegen bridge on first day of airborne landings with a coup de main grab of main objective instead of focusing on Groesbeek heights , Guards Armored Division would probably reach to Arnhem within a few days) It was Gavin’s and Browning’s blunders that sabotaged Market Garden ground advance.
Only successful coup de main grab of bridge during Market Garden was accomplished by 504th US Airborne Regiment during the operation , that was independent of Gavin’s interdiction , landed on Grave bridge on Maas river and captured it in a few minutes after landing on 17th September. (ironically this regiment had not participated Normandy Landings , previously came from Italian Campaign but aware of shock and suprise advantage of airborne operations more than “veteran” units and commanders) I believe it was later named as John Thompson’s bridge , after US lietutenant who captured it on 17th September.