A lot of people do pay for access, and that includes watching the occasional practice. Not quite the same as charging at the entry, but it's a slightly more genteel way of achieving the same end -- more money.
And yeah, pretty soon it's going to cost to do just about anything related to collegiate athletics. Expect ticket prices, donor programs (like Tide Pride), and required additional donations to things like the Crimson Tide Foundation to increase. Then there's donations to pay-for-play collectives like Yea Alabama, though I expect those to be absorbed into the Athletic Department as it becomes legal for the schools to pay the players directly (if that hasn't already happened).
Today, schools are at differing stages of the process. But eventually every school, not just Alabama, will be doing this.
If you want to stop the insanity and just watch from home, you won't spend as much, but it won't be free. You'll be paying more for ESPN, and I expect broadcast network TV to go to either a pay-per-view or streaming subscription model.
As Buzz says, at some point fanbases will reach their collective choke point. I'll put the over/under at 5 years.