But don’t you think your desires would grow accordingly? To go back to my “medieval peasant” example, a simple shirt is something we take completely for granted and is arguably “post scarce”. But before industrialization, people would think of a shirt sort of like we think of cars today. It took months of labor to make one, and it cost orders of magnitude more what it costs today. So to those people “I would own a couple of really nice shirts” would have been a reasonable goal to aspire for. They simply could not imagine cars or iphones.
Your second point is an interesting one. I do think we’re gradually moving to a world of artificial scarcity (brand names, luxury goods, bitcoin etc.), plus some things will always be scarce by nature (access to important people, people’s time). So perhaps we’ll just discover that the connection between resource scarcity and human desires is accidental.