I would not classify it as anecdata. This was research backed policy adopted by most US universities. Residential life and the Dean of Students office are usually doing a lot to cooperate with other universities. This part of US colleges is not competing with each other so they routinely share data, go to conferences together multiple times a year, and res. life directors move from college to college every few years so they all know each other incredibly well.

The point is that everyone who gets a single is super happy about it the same way that a drug addict is always happy when they get their drug of choice for free: of course it’s great. Of course it isn’t the best thing for you in the long run. I say this as someone who hated being in a double my first year and spent the next three in a single.

As far as I am concerned having apartments of 4-8 students where each has their own small room but shares a common space is ideal. But usually this is reserved for sophomore year and later.

It depends on the person. I lived alone in my last year of undergrad and it sent me into a deep depression. I figured out that living alone was too much isolation for me and moved back in with a roommate. That helped to pull me out of my depression and be able to finish my degree.