This isn't that surprising, given the power concentration in college football, but I guess I came into this season thinking there was more wiggle room for the other conferences. As this season has played out, it looks to me that the pattern is likely to continue most years. The big downside to this is that there's only going to be one spot available for a second team from the B12/ACC/other, and no extra spot at all in a season that ND makes the playoff (as looks likely this year).

In both P2 conferences you have at least 4-5 power brands that will be given the benefit of the doubt in preseason polls, and it will be "good for college football" if they are relevant:
B1G — Oregon, OSU, PennSt, USC, Mich, Wisc
SEC — Bama, Georgia, LSU, Tenn, Texas, OU

If any of them slip up, you have some brand names that are going to occasionally overperform by virtue of getting lucky in their conference scheduling. They'd be likely in the CFP if they only have one loss, or if their second loss is in the ConfChamp game. Teams such as:
B1G — Iowa, Nebraska, Washington, MSU
SEC — aTm, Fla, Ole Miss

That's about twenty teams that would almost certainly make the CFP if they had one or perhaps even two losses. The odds that eight of them (40%) pan out that way are pretty likely. This looks like an overall down year in the BIG with most teams (including the defending champs) having four losses or more — and yet, they've currently got four of the top five CFP spots.

And then, you'll still have the long shots that sneak in, like Indiana will this year. Unranked in the preseason, might be legit, but played nobody out of conference and managed to draw only the lower performing schools in their large conferences that are always going to have some soft spots. By rising toward the top of the P2, their only loss potential is in the conference champ game, or against one of the teams playing in it. In any random year, Illinois could do something similar; or Maryland; or UCLA, Auburn, SoCar, Arkansas, ect.

I hope I'm wrong, because this is unwelcome news for all of us outside those two conferences. They just start out the season with so many pathways to get four teams in that BYU will always have to fight for the one guaranteed spot we can count on.