I think the general principle of not undermining your children by making their lives too easy applies to all financial levels.
Lots of people on here say they would never ask their children to leave home and are happy for them to live into their twenties, even thirties at home. I have seen the consequences if you make it very very easy for children to live at home and I don't like it- I think if all they have to do is earn pocket-money or 'extras' and their basic living is taken care of, especially in a house that is much nicer than the one they could have at that stage in life, then it takes away a lot of their motivation to go out and seek work, a career. We see this a lot on mumsnet with mid-twenties, often men but not always, kids stuck at home and just not really going anywhere.
I will always share my extra money with my kids, my parents do with me, so that's things like I'd fund them clothes they like, a holiday, house deposit (but that might be a loan depending how much money I have at that time), dinners out, things off Amazon.
I wouldn't want to be paying for them to live after uni on an everyday basis, unless they were firmly fixed in a good job and just needed somewhere to stay before making their own way.
I think the idea of multi-generational households is a good one where the children grow up to be successful adults themselves and then house older family- I think if children never really leave and just drift on into twenties or thirties needing very little, this can impact motivation. Same for the Nicoles of this world.
I am deliberately not letting my children convert my attic to live in or one person I know built mini-flats for his children in the grounds of where he lives, now most of them live there, you need to establish motivation to live your own life.
Money that helps the great life they are already seeking, or stops them being in an awful situation (e.g. private healthcare), yes, money to live on so they don't have to seek a purpose or career or have a reason to get up and go out, no.