I agree. It has killed some of my ambitions and changed others. I've done the simple living thing for my entire life, so I was never into consumer culture and acquiring stuff, but I did care very much about having a high salary, advanced degrees and things like that. This is because I viewed these kinds of things as hedges against the precariousness in which I'd been raised: dad laid off all the time, living on pancakes and pasta, and seeing every grocery store trip and new pair of school shoes drive my parents to extreme stress and misery.
The turning point came sooner than I thought, though. As soon as I realized I could buy everything I wanted at the grocery store, my ambition started to slip. Realizing I didn't want almost anything, ever (because most things are cheap, slave labor crap), accelerated things. Paying off our house was the nail in the coffin, which I did not see coming. We're a few months into FIRE before age 40 and my striving/professional ambition is dead and gone. My creative ambitions, on the other hand, are roaring. My capacity for sewing, writing, knitting, cooking, home brewing and woodworking are endless, and those are the only things I can compel myself to do. And I have all sorts of things I'd like to do with them. It feels different though, in that I genuinely don't care what happens with these pursuits and will pursue them no matter the outcome.
This lack of ambition does make me feel like my advanced degrees and previous striving were wasted, but they did probably help us reach FIRE as soon as we did, even if I don't know exactly how. Mostly I'm just stunned at how quickly and completely it evaporated. Pfffsssssshhh.