*I’m going to go against the grain here slightly and say they went into their own rooms from a young age not because it was what I wanted, but because I genuinely believe that it’s a huge gift to give a child to teach them to be able to self settle, to benefit from having their own space, to feel happy and safe in their own company, to actively enjoy time on their own - whilst always being absolutely confident and secure that we are there for them if we need them. And by settling them in their rooms from a young age they all learned this very naturally.
I’m not at all sure that long term co sleeping necessarily has any benefits, other than to make the attachment parent types feel superior.*
Yet here you are and you are coming across as thinking that your way is superior.
Why can't people accept that babies and children aren't robots and they don't come with instruction manuals. They are all different and what suits and works for one family won't necessarily for another.
I've had one child who slept fine in their own bed, another who slept with us until about age 4. Neither way is 'right' or 'better', just better for that child and our circumstances at the time.
Anecdotally I know of two adults who slept in their parents beds long term as children who have turned out to be lovely people who've done perfectly well in life in good careers and happy relationships. Equally I know two adults who slept well as babies and children who've grown up to have insomnia and severe mental health problems. I doubt how someone sleeps as a child makes much difference to anything.
To think that you're way is the best way or the only way is sheer arrogance.