Beating Chattanooga and Middle Tennessee and barely beating auburn and having close games with arkansas and Texas A&m and losing to Texas isn’t enough to put one in the national championship.
FSU beat rival Florida and Louisville without their starting qb. Not stellar, but it shows that the team as a whole is very good. Undefeated means a lot.
Alabama is very good....but the decision was probably made considering Alabama’s viewership drawing power and rich history. They certainly have a chance to win, but I would guess there are 2 or 3 other teams who did not make it who could also. Namely Georgia, Ohio State, and FSU.
There are several strength of schedule rankings out there, and FSU isn’t particularly impressive in some of them.
http://powerrankingsguru.com/college-football/strength-of-schedule.php
https://www.teamrankings.com/college-football/ranking/schedule-strength-by-other
Bama is for football for ESPN as Duke is for basketball. The network makes sure they’re protected.