This question is impossible to answer without just pure guessing.
Sony & Microsoft are huge companies with fingers in many pies, for them to actually dissapear would take multiple huge market shifts and failures on their parts to invest in up and coming techs (and artists/studios too in Sony's case) And it would take years if not decades for them to die this way... which wouldn't happen because the people running the company & investors would make the neccessary changes before the fact.
Nintendo is different in that it is only really focussed in one area, thus making it much more vulnerable (PC and Sony/MS are major threats to the home console business and smartphones to the handheld market) but they are also a very careful company with huge cash reserves. I would say it's possible for Nintendo to be killed off in maybe 20-30 years if they don't do things right, but again it would take a few years and their cash reserves can hold them up if need be while they restructure.







