You described almost a very insta perfect version of the experience which doesn't play out most of the time.
I think this sort of response is extremely rude, and I know how dismissive and silly it sounds. It’s also extremely off-putting without adding much value. It feels like you’re looking for a reason to explain away their positive experience. I think the reason your comment has me flustered is that OP seemed to implicitly address many of your questions. Finally, is having a nuclear family really so remarkable and rare as to be a privilege worth sussing out?
And students literally are killing themselves at universities because of how well they are "set up by their parents" to succeed. This whole line of thinking seems extremely naive when it comes to what people have to sacrifice to succeed in any pursuit in life. Personally I'd say the single most important thing needed to be happy in grad school is friends and a social life. Like everywhere else in life. Liking what you do comes in second.
I got a PhD 30 years ago, and had similar advantages: Supportive middle class family (both parents scientists), free ride plus stipend thanks to NSF, met my spouse there, etc.
I think that while it's correct to point out the benefits of such advantages, the same advantages apply to success in almost every realm, from K-12 through college, in business, even in the arts and professional sports.
Fields where a poor person has a chance at overcoming the obstacles and getting a lucrative job are few and far between, and computer programming is the only one that I can think of.
Note: I chose the word "chance" carefully, not "certainty."
What was your family like, stable nuclear family?
No - child of divorced parents
Middle income, - yes
did you fully support yourself, on your own during your studies? - my dad chipped in $4k toward the first year of undergraduate, after that I was completely on my own.
Did you have any other work or responsibilities? I did work through school - event setup, grounds crew, working in a computer lab, and eventually working with a group on campus that helped professors put their courses online.
Did you get cash or material gifts and support from family? etc etc. - nothing beyond the $4k mentioned before. But I did get straight As, so I had academic scholarships that helped with tuition. At least during my undergraduate years.
“… which doesn’t play out most of the time.”
I had a great time in grad school and think it was definitely worth it, and you don’t have to be rich to go, but at the same time I wouldn’t recommend it if you have others financially depending on you.