Are 4 years of living in dorm rooms stressful?

Yes it would be. 30 weeks of 1 year was enough for me.

Student life is not the same as a working person life.

Depends where you work. I just moved to SF and it feels exactly like being a student again, from communal meals to company run outings to the thrill of being in a new city.

I'll probably spend a year or two in a studio apartment slightly larger than the ones in the article and then find a house with housemates, just like I did back in uni.

I think it's fine for a student, or temporarily. I wouldn't necessarily want to live in a tiny nor shared space if working full time.

Only if you are a hermit.

Think of it as a bedroom. People don't spend too much time in these. Further, as the article pointed out, they have shared communal areas.