What a weird martyrish attitude. Thank god, my whole family and even relatives think like your ex and not like you.
My dad's also wealthy. Funny enough, he got a 'leg up' as you call it from his parents, they paid for his studies, bought him his first house and helped him financially when he started his business. They did it with all three of their kids. It didn't turn him (or the other two) into some useless human being, his business was very successful, he multiplied his wealth many-fold since then, bought multiple properties, land, etc since then.
He did the same two us, my sibling and me. Paid for our studies, bought us homes, helped out financially when we were very young. We're both doing great now, too.
He has more money than he could possibly need (his words). So instead of making his own offsprings' lives easier and more pleasant, he'd better keep it in the bank and see us struggle with mortgages, etc? Just....because? So we would experience struggle, hardship and 'real life'? We're both working, we're not sitting on our arses and he's happy with that.
I'll definitely follow my grandparents' and dad's example and not yours with my DD. It's moronic to make your own flesh and blood suffer if you have all opportunities to prevent it.
If my mother thought like you, I'd cut ties too, tbh.