Exactly. It isnt the NCAAs fault that there is no money to be made anywhere else playing football short of the NFL or CFL.
The NFL does not want or need 18 and 19 year olds. You could probably count all of the players that were physically ready for the NFL out of high school in the last 30 years on 2 hands, maybe 1. They have no incentive to draft high schoolers when 21 year old professionally trained players pour out of college every year.
The current college system is the best option for an 18 year old football player, by far. A small, small percentage could be drafted after 1 or 2 years, if allowed, but that's not a major issue. They are free to sit out and bang on the NFLs door all they want until they turn 21.
The only way to keep the integrity of CFB as an amatuer sport with an artificially leveled playing field on which 100+ teams can reasonably compete is to not allow teams to pay or buy specific players.
I'd rather lose the 5 guys per team that would actually make any money on their own merit than destroy the college football game that we know and love.