Maybe - the money is currently being sent to conferences for whatever reason to split. That is a major source of revenue, but it isn't the only source. Being in the postseason on a regular basis could also, theoretically, improve a team's revenue. In any event, without any sort of automatic qualifier, there isn't much incentive to be in other leagues, so I wouldn't just conclude that.
Also, the NFL merged with the weaker AFL and that seemed to work out.
Well, the money is not necessarily causative, but correlates with a lot of other positives. Some of which might go away if you move to a weaker conference.
I.e. I posted upthread about my previous lament that Darrell Hazell was recruiting at a MAC level. In truth, when I started looking at recruiting classes, his teams on paper would DOMINATE the MAC. The worst recruiting program in the B1G over that 4 year stretch and it was FAR better than anything in the MAC.
So you might ask--why does Purdue get its teeth kicked in repeatedly in the B1G instead of dropping down, and then kicking ass and taking names in the MAC?
Well the answer, in addition to all the money of course, is that if Purdue dropped down to the MAC, they'd start recruiting like a MAC team instead of a B1G team. Purdue recruits know they're going to play in big games on national TV, even if they're likely to lose them. MAC recruits, well, don't, unless it's an annual paycheck game to get your teeth kicked in by a B1G team.
That's a more stark example than say a B1G or SEC team moving to the B12 or ACC, of course. But programs move up for aspirational reasons when the opportunities arise, not down to beat up on weaker competition. Because teams often rise or fall to the level of what's around them. If Penn State left the B1G and moved to the ACC or B12 to have a better chance of winning their conference, would they still recruit like Penn State?