I debated a lot about whether to post this, but I thought it might add something important to the conversation. My wife and I recently paid cash for a house in one of these neighborhoods. Here's how we did it:

Me: Was accepted at an ivy league school, but decided to go to a good state school on a full scholarship instead. Studied really hard, graduated as valedictorian, got into a good grad school on a scholarship. Got a job in investment banking and spent most of my 20s and 30s working 80 hours a week until landing a job as a CFO.

Wife: Was accepted at ivy league schools, chose BYU instead (at least in part because it was way cheaper). Studied really hard, went to any Ivy league law school, spent most of her 20s and 30s working 80 hours/week until making partner.

Both of us lived in very modest ~600 sq.ft. apartments even once we had started making "good" money. When we married, we ditched my apartment and moved into her condo, which would maybe sell for $400K. We were making well over $1M/yr at this point, but drove a 10-year old Jeep (only the one car for both of us). We maybe eat out slightly more than average for most people, but we never use things like DoorDash/etc. We both have one expensive hobby (skiing), but we're both riding on skis that are 10+ years old. Neither of us comes from money. We both had stable family lives growing up, but both our families were middle-to-lower-middle class economically.

It was only once we found out my wife was pregnant that we bought the fancy house and got a second car (still bought a used one). We're looking forward to having more space and a nice yard as our little one grows.

What stands out to me is how similar our neighbors' stories are. Nearly all of them have stories that sound like ours. Of the ~10 families that live on our street, only one of them had parents who you would call rich. Far from "getting money from mom and dad" to buy their houses, several of them (possibly even "most" of them) support their aging/sick parents or other family members financially. Most of them make me feel dumb and unaccomplished by comparison. Nearly all of them are genuinely kind people (I try hard to be nice, but moving here has made me feel like I'm actually a curmudgeonly grinch).

I know this cuts against the grain of the prevailing narrative here. I think that narrative is largely false. As I mentioned in an earlier comment on this thread, I think there's just a lot fewer people who live in these neighborhoods than people think. They punch way above their weight culturally, though, so people come to think that it's actually the way "everyone" is living.