Not surprising to see such a thread after people got a glimpse of where Sony is heading, but people need to think about why it's happening before they jump to the conclusion that every console manufacturer will go down that path.
1. The first thing that people don't understand or keep forgetting is that gaming has two major points of origin. One point is the arcades which spawned dedicated gaming machines to bring the arcade experience into people's homes; the other point is PC gaming. The major difference between arcade and PC gaming is that the former had to be about games that can be quickly understood and learned because otherwise people would have just moved on to the next cabinet to put their coins into; on the other hand, PC gaming was known for complicated setups and lacking ease of use, both in how to get games to run and how to play them, but that is owed to developers knowing that people are going to be sitting down to get into it.
2. The second thing is that not all console manufacturers are the same. Nintendo is the last remaining company that makes traditional consoles because they are following the spirit of arcade gaming. Sony may have started out that way too, but in hindsight it's clear that that was just about getting a foothold in the console market, because with the PS3 it's already evident that Sony was pursuing PC gaming on consoles all along. Microsoft launched Xbox as a defensive measure, because if PC gaming was going to move to consoles, then at least it should happen on a Microsoft product. (Gaming PCs use Windows as OS, so a part of Windows money has always been from gamers upgrading to new rigs and new Windows iterations.)
3. With Sony and Microsoft consoles becoming more and more like PCs - the Xbox Series X doesn't even try to hide it with its hardware shape anymore - it seems natural that PC gaming is going to return where it belongs. Obviously, Nintendo isn't going to take that path because their idea of console gaming clashes with all the major players in the industry. However, Nintendo's path doesn't clash with the market, so why should Nintendo change. Before Switch, it was said that Nintendo has to do the same as Sony and Microsoft, then Switch was unveiled and immediately doomed because Nintendo did their own thing. Turned out that the more Nintendo goes against what Sony and Microsoft are doing, the more successful Nintendo is. Switch wasn't the first time either, because the Wii and DS told the same story.
4. The biggest factor in gaming profits are subscriptions for both Sony and Microsoft; on the other hand, Nintendo makes most of its money from game sales while being profitable in all other aspects as well. This is a crucial thing to remember because it's about the business motivations of all these companies. For Sony and Microsoft it makes the most sense to include the PC and similar devices to expand the reach of their subscription services because they typically sell console hardware at a loss. On the other hand, Nintendo's core business is profitable in all areas with only the 3DS and Wii U being outliers. The design of Nintendo hardware is also integral to the gaming experience; currently, Switch's portability differentiates Nintendo in a major way from all other options and that's something that will continue going forward as generations pass, so for Nintendo the tradeoff of foregoing exclusivity of their games to sell games to a bigger audience isn't worth it, because that way they'll lose out on profits from other areas as fewer people would buy their hardware.
5. Regarding Microsoft, I don't think anyone doubts that they'll be more profitable without a console, because after almost 20 years in the console business, subscription models are about the only thing they have to show for it. Regarding Sony, what leads them to doing what they are doing is Microsoft's direction. If Sony allowed Microsoft to establish themselves as the leader in subscription services, then Sony's profits would eventually begin to suffer. The major players' assumption that streaming and the like is the future may all be wrong, but nevertheless it's what they believe in and that's why they go where they are going.