It matters everywhere, but the SEC just has so many built in advantages when it comes to recruiting. Florida, Texas and Georgia are all in the SEC's footprint and those are 3 of the most talent rich states in the country, and the gulf coast states produce a lot of talent relative to their population as well.
Ohio State and Penn State have advantages over the other B1G programs due to in state talent, and Ohio State is a big enough brand to be able to recruit nationally, but for whatever reason, much of the midwest just doesn't produce a lot of talent.
The west coast is very much a fairweather area. I remember USC used to play in a packed stadium under Carroll, but they might have had 10,000 there for homecoming this year. Get USC go on a playoff run and the west coast interest will be back in gear.
But nationally, I understand why a lot of people decided to not watch the NCG. They just saw those two teams play each other a month prior, and neither were met with any kind of resistance in the semis, and people outside of SEC land are tired of the SEC, and there's Bama fatigue as well.
I wouldn't be shocked if it was the highest viewed sporting event in Georgia ever, but Georgia doesn't really have a national brand.
I guess it's really more of a south thing than just the SEC, Ohio State is the only team not in the south to win a natty since 2005, and it was just one, so in 16 years, 15 of them have been won by a team from the south. To get more national interest back, teams from other regions need to start winning, and it's easier said than done. USC keeping Cali kids in Cali would help. I mean, Bryce Young won the Heisman for Bama and he's from Cali and Brock Bowers was the best TE in the country as a true freshman and he's from Cali.