How would having more money make them discontent

When they were less well off than Britain, they liked being British because they were protected by the British army and received British investment. Once they were richer than the rest of the empire, they wanted to be independent so that they didn’t have to support the rest of the empire.

In addition, the Royal Proclamation of 1763 limited the right of British colonists to use the land to the west of the Appalachian mountains. To the British in Great Britain, this was no big deal, but to the colonists it limited their expansion westward. The Quebec Act in 1774 vastly expanded the size of the Quebec province and allowed the French-speaking, Catholic “Canadiens” to move south-west and settle in areas to the north-west of the 13 colonies.

Yes, in public people talked about high-minded ideals, but the reality is that the defeat of the French meant that the American colonists no longer had as much of a need for the British army. In fact, the British army was standing in their way, stationed between the colonies and the new “Indian reserve”. And, although taxes on the American colonists were much lower than taxes within Britain, the colonists didn’t want to pay the taxes, even though it was paying down a debt that was mainly due to kicking the French out of the new world.

It was an economic decision, not a moral one.