I finished university in 1988 and my best friends are 4 people who were in my first year accommodation. Over the years there have been times when we've been living in 4 different countries and 3 continents.
My daughter has just finished her first year and next year will be in a house with others from her first year campus residence. As above, they get on, and go out together often. Her best friend from the year though, and the one she's on holiday with right now, was in a different residence this year and will be in a different house next- again, because as above, often second year accommodation needs to be sorted before Christmas of the first when you are all getting to know each other still. Mine was also surprised (having heard me talk about my experience) how often some of the people she knows go home. Some go home every weekend. Possibly because they have jobs, for financial reasons, or simply because they want to- I guess their best friends are still going to be the ones at home.
I do think the university experience for some has changed over the years- as a teacher I'd say so has the school experience and life of teenagers in general.
I don't think it's to do with online lectures. I think it's to do with a combination of online life telephones, the internet, gaming, FOMO meaning that instead of actually living their lives, a lot of teenagers (and not only) spend a lot of time watching what they think is other people living theirs, a reduction in socialisation in general, and the absence of that "benign neglect" from parents that other generations had. There's also the increase in students who decide to live at home, for financial reasons and others. On my course one boy lived at home and that was because he'd chosen one of the universities in the city we were in. He didn't come back in the second year. It was almost unheard of for people to live at home.
TL:DR Some will find their lifelong friends in halls. Some won't.