Market Garden was a partial failure. The major objective was never achieved as part of this organization. Several things led to this:
1. The earlier stop by Montgomery after seizure of Antwerp resulted in the failure to seal off the Scheldt and the German 15th Army was able to participate in the german defense - forcing the Allies to fight on three sides while advancing towards Arnhem.
2. The British 1st Airborne dropped too far from their objectives and only LTC Frost's battalion reached the highway bridge. The British could not defend the bridgeheads and their drop zones with the available forces.
3. Reference comments about British tankers - there are reports that after the Guards Armored Division crossed the Nijmegen Bridge, they stopped for tea, when there was some opportunity to gain valuable ground while the Germans were still off-balance.
4. Another problem was limiting the avenue of advance to the Nijmegen highway, when there were parrallel routes that would have given the XXX Corps a broader front, more river/canal crossing sites and put more pressure on the Germans. I have driven Hell's Highway from the Belgian border to Arnhem and to make it sole route was a serious tactical and operational error.
5. But the biggest error was the complete rejection of available human intelligence from Dutch citizens and from other sources. Allied Command completely discounted the presence of the 9th and 10th SS Panzer Divisions stationed outside Arnhem
6. Even if XXX Corps had gained the Arnhem Bridge there is no guarantee they could hold the narrow lane all the way from the Belgian border and been able to gather sufficient combat power to cross the North German Plain. The Germans still had significant combat power, evidence the 2nd Ardennes Offensive. If Montgomery had received all of the supplies he needed to conduct his Northern excursion to Berlin, the 12th and 6th Army Groups would have been at a standstill. This would have freed a lot of German divisions to strike into the flank of 21st towards Antwerp, and the Germans could have made it. This would have isolated almost the entire British Army in the Netherlands.
Just some thoughts.