i second TnT: it is better to be here than try to get back here.
i would not say for a second the best 16 teams in the US are in the NBBA -- and there some really good teams who are fighting tooth and nail amongst each other to get here. really good managers, those with a sparkling record of long success up here, teams like the Bruins, Silverbacks, and Burlington, once they dropped down, have stayed down (although i think it is at least partly their choice). i know some teams / managers who have for one reason or another had to move down -- Kurgans, Yuck, the River Dogs, Rocket Science -- and they know how to assemble a team and may stand in your way to a rapid return to the NBBA. and you defeated perhaps the best non-NBBA team, the Clogs, to get here. try doing that again! i would not set that as a task for myself.
if you have a plan, then you are right, you can pile up a pretty good stash here, and that can give your future team a solid foundation -- but remember young-ish impact players at this level run $2 million plus, and training players to that level take four, five or more seasons.