Isn't shane just money in the bank..

[bzkfn]

I was wondering if PBF, and manny dont fight shane, could the reason be that they know that fight will always be there, and if and when one of them loses again they can cash that mosely check...

Maybe. But it could be down to how long he has left. The longer they leave it, the more likely it is that Shane fades with age. Plus he's basically waiting for a fight with one of those two or Cotto, so they don't have to rush things.