NCAABB has a comparable number of teams and has a tournament of 64!!!
Actually, NCAABB has 200 more schools than D1A NCAAFB. It's a lot easier to maintain a D1 BBall program than a D1A FBall program.
Regardless, the tournament puts 65 teams in (out of 327 ~20 %). 20% of the football teams would be a 24 team cut.
You've also got 32 conferences in college basketball. These get automatic berths into the tournament, leaving ~half the tournament slots open to at-larges. If you were to give every conference in 1A football an automatic playoff berth, you'd fill up 12 slots, leaving only 4 at-large open if you were to do a 16 team playoff. Tell me someone wouldn't whine about Troy making it to a playoff and Ohio State or Michigan not.