the franchises are schools (or said differently, franchises are run by schools and carry the school colors, logo, mascots, etc).
There was no age limit or eligibility limit. Simply teams putting together the best teams they can with available people. Less HS kids would get a shot, but just like in the NFL you’ve got guys retiring each year, declining in ability each year, etc. that clears enough room for HS talent to enter the league too. The quality of the football being played would go up.
It sounds terrible on the surface because it would really change the look and feel of college football from yesteryears, but as I think about it more, there are certainly some pros to taking this path as well and it may not be too different than the free agency free for all we have had the last few years.