No one really knows what will definitely happen in 2042, there are unfounded rumors of contract extensions etc., but as our contracts read now, DVC's "right to use" lease will expire and the properties revert to control of WDW for the company to use, demolish, or re-sell as they see fit. DVC owners don't actually OWN the land, we own buildings and improvements located on land leased from WDW. It is possible DVC will renegotiate, rehab/rebuild and begin a new DVC type program.
OKW is the only one big enough to do something different - I think the DVC resorts will just become part of the hotels they are close to for the other ones and WDW will rent them.
Of course that is my opinion and I really hope that I am wrong. I think it really depends upon how popular WDW is at the time - if it is increasing popular - I don't think they would renew DVC - why- they won't need to - but if the current situation in the world economic kepts getting bad - they need us now - who knows that the future will be.