Great point. Add to that the lack of family atmosphere in the pros - Don't get me wrong - teams try, but players can be traded. Once the season ends, players disperse - to go over seas, or train elsewhere, etc.
And it isn't just that, in college you live right next to all your teammates (except the freshmen, who are still within walking distance) and you are all doing the same things every day, and you are all nearly the same age. In the pros, while you
may all live in the same general location, you may be an hour's drive apart, or even just ten minutes, but it takes planning and organization just to drop by and hang out with one or two teammates, let alone the whole team. And while you have the same job as your teammates, each year away from college your lives diverge exponentially - how many common interests do 21 year old Jewell and 35 year old Sue really have beyond basketball? Or mother of a young child Parker have with the rookies LA will bring in this year? Or a European with an Australian with a Brazilian with a US college graduate?
There is the commonality of the team goals and the game, but you are likely in a new city in a new region of the country, renting your first home, paying your first monthly utility bills, buying food and making your meals, and managing your free time - it is a huge change in lifestyle, and you are experiencing that change alone unlike that first year at college where you are surrounded by thousands of people experiencing the same issues. Yeah you have some help from your new teammates, and the team itself has a support system, but oh my goodness, we ain't in Kansas no more!