Military defeat ended the war before serious armed conflict erupted in England - indeed at the time the regime seemed on top of things at home. But the subsequent turmoil certainly made another French venture less likely, at least until the 1470s. Causation may have run the other way, with the loss of overseas battlefields leaving a lot of disappointed English knights with too much time on their hands, and the disaster in France certainly provided political ammunition for the Yorkist side in the early years. Money was also at a low ebb in the third quarter of the century, and while France had manpower, English expeditions relied heavily on money that only became plentiful again after around 1470.

No, quite the opposite actually. The War of the Roses was largely the result of the loss of traditional English territories in France during the final phase of the Hundreds Year War. The Duke of York was angry at the Beauforts for losing Normandy which he had successfully defended, Henry VI's first mental breakdown was caused by the English defeat at Castillon. The war was financially costly to major noble houses and York in particular was angry that he had personally contributed large sums to the war without being repaid by the crown. Both sides had access to lots and lots of newly unemployed soldiers returning home from France to fight the war with.