Which reporters?
There are a lot of CFB expansion accounts that make vague predictions and are often wrong. The ACC GoR seem extremely strong.
At this point the money doesn't really make sense to add any teams. Furthermore, the B1G doesn't need to improve the football product on the field. The conference is already extremely difficult and they will likely have 2-3 teams qualify for the playoff every year. Adding FSU and Miami will just create a conference where the top teams all end up 9-3.
CFB is moving to 12 team playoff, and 9-3 might get you in (borderline), as long as you are in the SEC. Or perhaps from the Big Ten. So don't be so shocked.
But also, look how much has changed in the landscape of college football within that past 4 years or so.
NIL - players getting paid. Transfer portal. 12 team playoffs. Super Conferences (OU & UT to SEC.... USC/Oregon, etc to Big Ten). You get the point.
If you can imagine, the playoffs might even make it to 16 teams down the road (meaning, in 3 years). Perhaps maxing out at 20 teams.
9-3 gets you in the playoffs, even if you didn't make it to a conference championship game (if that still becomes a thing).
Why FSU and Miami to the B1G? Well they are not feeling it in the ACC, they see the ACC projecting downward while the SEC and Big Ten are projecting upward (and the $$$$$$ millions that come with it).
And finally, if FSU and Miami want to come to the B1G, you let them and you accept them and you embrace them. You have the best of the West Coast, the Midwest, some of the East, and you add Florida.
Otherwise, if you don't accept them, they will just go to the SEC. But it is their preference to join the Big Ten, and that makes it even more snazzy if you ask me.
Hope this helps you comprehend the future of college football. NiL. Transfer Portal. CFB playoffs. Big Money. Big Payouts. Joel Klatt. State Farm. ESPN. Podcasts. Fox Sports. Gus Johnson. Pat McAfee. Bevo. College Gameday. Reece Davis. Matthew McConauhey. The world is upside down. And FSU & Miami would like to join the Big Ten Conference. Make sense to me and lots of people. Hope this helps you understand.