It's a bit of both here. Yes people leave there jobs every single day for different jobs... usually leaving their current job after having another job ready to go (not always but a lot of the time). A couple of recent polls and studies are showing consistently between 40-45% of the kids don't find a new team with only about 4-5% of those kids returning to their original school.
If 40% of employees in any field in America quit and then didn't find a job.... yikes.. its like real life in that these kids a selling a particular skill set and can't be "retrained" either.
We have seen a continuation of the instant gratification/success model get worse and worse... There isn't a way to fix it easily. The system took advantage of its labor force to the tune of billions of dollars and that time has changed. Player/employee empowerment hasn't been this high in a very long time, but empowerment with out direction on how to use it is going to destroy the smaller schools and in the process hurt a lot of the players as well.
Small schools may have to return to the mission of education and if they want sports Div II and III might be the landing spot.