Now we're not talking about some small low rent apartment like most of us lived in during our early twenties. Again keeping their grip on reality, none of them had to go through searching for a place, signing a lease, or actually paying rent. Instead, we get to see them arrive with their luggage in hand ready to move in. When The Real World was just starting they kept up the pretense that these people were somehow randomly chosen. It's been clear all along that the roommates were carefully chosen on the basis of how well they'd look an television.
Most people choose roommates that they believe they can get along with to reduce conflicts.
A lack of conflict would make for boring television so personality types were chosen such that they would inevitably lead to some conflicts. Also, lets throw in several different races and sexual orientations because that always makes things interesting. The residents job is to do promotion for a local Seattle radio station. That's not so bad. At least they have a job.