My parents are super social to the point of inviting over colleagues for dinner regularly, but I think they're also so social (and worked for nonprofits that are more like family) that they simply have so many options that the ones they pick are much closer work-friends that often last decades.
Other people really do just want to go home and do their own thing. As long as no one is rude, there's room for both.
I find that after spending that many hours with work friends I rarely want to spend extra time with them when I could spend that time connecting with existing friends I haven't seen in a while who I'm already very close to. Balance.
I've rarely had a work friend turn into a real friend though, but I'm also totally happy with that. I need breaks from people and don't want to get sucked into the work as life mindset. I'd rather meet new people at... pick a hobby. Dancing, singing, karate, whatever. That's how I make new friends, through hobbies rather than work because work friends dominating my social life feels incredibly unbalanced.
One draw back of that is my professional network is limited as well, in times of economic decline a robust professional network is often the key between employment and not
That's all professional relationship building though, I truly don't think those people are ones she'd invite to a movie or over for dinner. Maintaining professional relationships does take constant low key attention though, if they only hear from you when you need something it's not a good look.
Isn't that how most people form friends normally though? Through a shared experience? Especially a tough or formative one? Friends you meet at school, in your first year at uni, in bootcamp, on a sports team, these are how most people meet their life-long friends.