It just comes down to whether or not those external factors, whatever they are, are real. Even in the case that they are real, but can be mitigated by talented administrators or coaches...the more resourced programs will buy whatever advantage has been realized and the lessor resourced program will sink back to square one. The fact that the good programs (Ohio St, Penn St, Alabama, etc, etc) are always good is part of the proof of these external factors but the real evidence is the fact that the bad programs are always bad. Why is UNM always bad at football...why is Idaho? There are versions in the big conferences as well. The schools that are in the position to draw the cream of the crop in talent will accrue to themselves an asymmetric advantage that, over time, will become more and more insurmountable. It's like boiling a frog...it's hard to notice it for a while, but at some point, you are cooked. This is how college sports have operated for a very long time.
The one thing that the big programs could not get around in the past was the problem of evaluating immature talent...plenty of unremarkable HS athletes have blossomed and dominated at small college programs. Now even that small problem has been solved by the complete relaxing of transfer restrictions and massive amounts of NIL dollars.
And to your question, "why have a football team?" I think I have already answered that....it is not, in the main, to win championships.
I think all this talk about what it takes to win is missing the point. Maybe I can anticipate your next question....Why do I (307bball) care about watching Wyoming sports if I know they aren't going to ever be relatively as good as they were when I was younger? That is a tougher question...and one I would not have had a good answer for until my son has come online with watching and playing sports. I am now experiencing it through his eye's. It's hard to explain. This year was one of the most enjoyable for me as a Cowboy's fan....despite having witnessed multiple greater years as a younger fan. My son and I went nut's when we got the two-point conversion to beat tech...I'll never forget the mosh pit in stands as the App St fg was blocked and run back and I don't think he will either. After the game, we went on the feild and I have a picture of him with Devonne Harris's arm around him! I know that this year's team is not as good as many of the teams I watched in year's past...but I can't deny the enjoyment I derived from it. Anyways...that is now what I'm enjoying. Maybe the NCAA will wake up and the people that care about real amateur athletics will create something that won't competitively disadvantage program's like ours .... but i'm not holding my breath.