Even with stagnation, the console business model is the best way to make money, and can be monetized more today than past generations.
There's a reason Nintendo is a lot more profitable now, compared to the Wii/DS era, and that's with 100M less hardware sales. Despite the struggles with margins, the PS5 is making a lot more profit than the PS4 launch aligned, with some of its most profitable years ahead of it. There's a lot of growth to be had on PC, and Sony is starting to expand in that space, but I feel like they wouldn't do day one launches until they had their own storefront.
I feel like its more likely they will try to have PlayStation Plus be more accessible on PC/TV/Cloud, like they originally planned with PS Now, an approach similar to Microsoft, but as a more complimentary part of their platform rather than a primary driver.