In fact, in a scenario where every team truly has a chance to participate in the end of season tournament, the regular season suddenly has incredibly more meaning.  Right now, about 125 teams have zero chance at a national championship before the first game is played.  Under the proposed scenario, every team has some chance to win their conference and have that conference be among the top 6.  In addition, 6 teams make the tourney as "at-large", which means that many more regular season games are going to have an impact on which teams make the tourney.

Today, a team is basically out once one of two things happen: (1) don't belong to a P5 conference; or (2) Lose a game.

Few NCAA football teams could pull a Los Angeles Lebrons and basically rest up during the season, show up for the playoffs and win a championship.  The one-and-done nature of football, combined with the impact of injuries, crazy weather scenarios and potential for upsets make this scenario impossible.

More access equals more meaningful games during the season.  

What I hear you saying is that you want the national champion to simply be the team that won the most regular season games against the best SOS.  We did that for about 100 years, and all it led to was a lot of dissatisfied fans and players.  Let's have a real tourney with the chance for upsets and exciting games throughout the regular season.  That is what is fun.