The people in the twins were not happy - they hadn't asked for them.
I knew one person who dropped out in the first 3 months (for mental purposes), and that was someone who shared a room.
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.
Maybe its fine for many extroverts, but forcing an introvert into a room with others is a great way to drive many people absolutely mental.