It may be imperfect, but it's not ridiculous. Certainly not as part of the larger picture. College football is still at least partially college football. People still have classes to go to and homework to do, and sometimes jobs to hold down and bills to pay, since they don't make hundreds of k a year.
They're still younger athletes who don't need to be playing a jillion games a season. With all the conferences and divisions, pro-style playoffs would take forever and batter kids into pieces. Can't do a 64-team invitational, because you'd still have to win six highly competitive games to be the clear-cut national champion, shredding our finest young players before their time. Cut the teams in half and you only save one game for the championship team and now, with only 32 teams from the entire nation, you're, again, deep into the realm of voting to decide who even gets a chance.
And this is just the beginning of all the challenges associated with picking a college football national champion. There's a reason people debate this stuff...nobody has a perfect solution. I could think of a very long list of sports issues which are far more ridiculous than voting for a champion.