curious, but prior to the 2014 did you believe that team was capable of what it achieved that season?
This is a fair point. I am 38 years old, so I certainly hope I have at least 40 more TCU football seasons in me.
We could say there are three factors which have to lineup for TCU to win the national championship:
1) Build the right team
2) Go unbeaten, despite the good chance you will be tripped up on either a) injuries, b) naturally chaotic and random nature of college football, or c) tough conference road games
3) Have good fortune with whatever playoff system/format is in place and have the right things happen in other conferences (totally beyond your control) to open the path to selection
4) Actually win those playoff games
The 2014 team clearly had #1, and #2 was so close to being in the bag. #3 was clearly where that team got screwed the most, but the Peach Bowl performance is strong evidence that #4 might well have happened.
The 2015 team proves just how crazy hard this can be. It still, arguably, had #1, but did not check #2 due to injuries. Think of how close that team came to winning in Norman despite the injuries, even after being blown out in Stillwater. Winning in both of those stadiums in the same season is always going to be a tall order, which means that, until the schedule pattern changes, TCU's best championship chances will come in even-numbered years only.
Even though 2017 ascended very high in the rankings, the roster was just flawed enough to give that team a totally different feel than 2014 had.
Only time will tell if things will ever align as well as they seemed to in 2014 again.