Depends how you define success for a club like Wrexham really I guess.
If the don’t get promoted to the premier league, the money will probably dry up within 3-5 seasons when the tv show and sponsorship dries up. but they’ll be left with state of the art stadium renovations and training facilities built around being a future premier league club.
They’ll have a squad worth a fortune based on their current spending trends which they’ll be able to sell off if required.
They’ll have gone from the conference to flirting with the premier league and having all their facilities re-built from top to bottom.
You could argue that it’s already been a humongous success and something from their wildest dreams already and they probably won’t just disappear back to the conference due to all the investment they’ve received already.