it might seem odd to say considering Nintendo's poor Wii U generation, but they are possibly in the safest position of all 3 to stay perpetually in the video game market. They could have Wii U losses for like 50 straight years and not go bankrupt (supposedly)
Microsoft has barely if EVER made any money on the Xbox brand. They always lose a lot of $$$ on the hardware end of things and the Xbox brand is almost certainly essentially a marketing investment from their eyes in terms of keeping the Microsoft brand and platforms (Windows) present in younger generations. Anyone thinking otherwise is not seeing the big picture or aware of their video game divisions mediocre returns (versus what they have spent). Microsoft spent a ridiculous amount in the first place trying to hedge their way in with the Xbox as well.
Sony I think is a big question mark because they are still quite divided, overall as a company, in terms of finances. Their TV, phone, movie divisions- none are doing particular well, and some have caused Sony to put on quite a bit debt (which I believe is still an issue).
I would say Sony potentially will be around for quite a while in the video game business BUT because they are extremely bloated in terms of overall company size and divisions, it does put them in an awkward spot of potentially being in danger (even video game wise) if some parts of their company do terribly.
I think the safe bet would be Nintendo and Sony outlasting Microsoft by quite a large amount. Nintendo has the strongest IPs obviously and then Sony has done a great job at making their hardware the most popular and generally trusted by the casual consumer. Both have great gaming brands because of those respective things
I can't emphasize enough how Microsoft is clearly using the Xbox brand as advertising and has put loads of money into it over the last few gens to keep the Microsoft name relevant for younger generations who may or may not otherwise care. When your software from Windows/Office is gigantic in sales next to your video game division I just don't know the viabliity of sticking with it permanently, especially when Microsoft does not generally profit that much from the Xbox
