I agree with Nekre Test will survive no matter what. Ask all the big name players they will tell you they wanna leave their name amongst the best in the longer version.
IPL is the only league that is capable of putting a complete stop in the Cricket Calendar. The best thing to do right now is to put IPL in the cricket calendar. IPL is here to stay, so everyone will have to adjust to that. In order for smaller leagues like BPL, SLPL, PPL to be succesfull they have to find small windows in the cricket calendar and try to host it. I can't see players like Steyn, AB, Pietersen choosing to play in these small T20 leagues over playing ODI or Test for their respective country. Not everyone is gayle or Pollard, they will want to take the breaks they can get to stay healthy so they can be ready for the next tour or IPL.