y did operation market garden fail?

Answer 1

Despite the reasons mentioned above Market Garden would have worked perfectly apart from one tiny problem.

Unbeknownst to the Allies, a German Panzer Division had been sent to Arnhem to rest and re-equip in a 'safe' location behind the lines. There were some recce photos showing German armour but these were discounted by the high command as a few straggling German units.

Unfortunately for the Paras they were heavily out-gunned by the German Panzers and although they fought most bravely, were inevitably overwhelmed before the Allied armour could break through to them. Added to this was the problem of terrain where the Allied tanks had to advance up a single road to get to Arnhem where they were sitting ducks for German AT guns and SPs. However, this would not have mattered if the Germans had not had armoured forces in the area to begin with.

Answer 2

The title of the book and the book of the film 'A Bridge Too Far' says it all. The parachute drops could not be supported by the promised ground troops and tank battalions because of the distance of Arnhem from the allied front line due to German opposition. The paras, despite valiant attempts, could not maintain or consolidate the bridgehead they were fighting for.

Answer 3

Weather was one factor in this. British and Polish elements need to stretch out their drop over days in order to get all of their forces to Holland.
Poor or Rushed Planning. One of the things that you see in the movie is the bit about the radios no working because they were tuned incorrectly. This is just one example of the left hand not knowing what the right hand was doing.