well this has been an interesting read. All of it.
To the OP, I went to grad school at an Ivy, granted I work in publishing, so I'm not rolling in the $$, but I understand the seduction of prestige and interesting, influential people.
I also did a whole lot of 'fucking off' and being away from the university->professional work treadmill until I got serious at age 28.
The one thing I learned from that time away was what mattered to me.
It wasn't status, it wasn't stuff, and it sure made me realize that I'm happiest when surrounded by people I like/love and doing something interesting.
In any case, I'm obviously different than you and have made different choices and priorities in life. However, if I was to be magically transported in your shoes, I know exactly what I would do:
1. Keep the high paying jobs and continue to live in the same area.
2. Downsize the house. Is it possible to stay within the same area (for your kids sake) but live in a neighborhood where people don't give a shit about how your lawn looks? That would cut back on a lot of your costs. Maybe this doesn't make much $$ sense.
3. I'd take the kids out of private school. Again, that's just me. If there's excellent public schools in the area, then what's the point?
4. I'd ditch the country club membership. If you're going to be FE in less than a decade, do you really need the value that these connections will bring professionally? As for the other reasons - friendships and recreation - you can easily get this for a fraction of the cost elsewhere.
I can appreciate how entrenched you are in that life style, so changing things drastically is easier said that done.
Good luck.