Is this a "my company of choice can't compete with Sony, so I hope they go 3rd party so my company can compete" kind of thing?
Sony is nowhere near the point of going 3rd party. They may stick some of their older games on PS Now, which can be played on PC. However, that is a streaming service, so it isn't as good as playing it on the actual HW, and it will take 2-3 years to get big exclusives that launch on the PS4 first. It'll also probably be 2-3 years before PS5 games start to appear on the service once it launches. As long as they keep selling 80M+ in HW, and use exclusives to help push that HW, they are never going 3rd party.
Really, the only ones who are in danger of going third party in the near future is MS. It doesn't help that there are obvious signs from the higher ups that they are less willing to put more money into selling more Xbox HW and have instead taken all of its exclusives and put them on PC. Scorpio almost seems like a last ditch effort by the Xbox HW division to keep itself relevant, hence them pushing it for almost a year. If it fails, I think MS is going to seriously think about whether to make a XB2 or not. They may give it one more shot, but if that fails, they are 100% done.
I think Nintendo, if the Switch continues to sell well, will have found their own market in the hybrid/HH market. If they can keep this going, they probably won't go 3rd party. However, if the sales begin to fall, I think they will try one more piece of HW, but a more traditional console. If that fails, then they could possibly go 3rd party. Though, I think Nintendo is not a definite until their cash reserves start to deplete to almost nothing, so they may continue until they have another hit or are forced to go 3rd party to stay alive.
