Last time I checked, Sony already was the top 7-8 biggest publisher in Steam history. Sony is very happy with their expansion to PC, which according to them it's very profitable, has a very high ROI and is bringing them new users to PlayStation. Plus is helping them grow in countries like China or Korea.
So I think they'll continue doubling down on it, growing even more with day one releases of live service games like Marathon and late ports of SP games.
I think pretty likely at the start of the next generation Sony will release their PC extension of the PSN storefront, where they'll sell directly their PC games, plus also will sell there 3rd party games. If smart, the games available in both console (including their upcoming portable) and PC PSN will feature seamless crossbuy, crossplay, shared trophies, etc. between the console and PC iterations.
Having defeated all their direct competitors in high end home consoles, I think their next step will be to expand their empire to start to conquer next PC and portables in the next generation with some aggresive push, while also starting to release the first titles of a future expansion to mobile gaming mostly via partnerships with top mobile Asian devs.
I think that to make PC PSN big will take a while, so in that period where they grow it they'll continue releasing their stuff in Steam at least some time after the release in PC PSN.
you guys always not counting Nintendo, they are clearly bigger threat than xbox.
but here we are...
Nintendo did stop competing directly with PlayStation when after GameCube decided to stop pushing for the high end visuals home consoles hardcore market and started to focus instead on a more casual and familiar market plus in their own fans and after the WiiU failure on portables.
Sony and Nintendo target complementary markets with little overlap, the success of one doesn't affect the other one. This generation they have been both breaking records in different areas.
In the near future it may change and they may compete directly again. With the successful experiment of the non-VR 'big' Astro Bot game, pretty likely Sony will start targeting some of these kid friendly/family demographics more seriously traditionally approached by Nintendo ('gummy bears' seems is going to be relatively similar to Smash Bros and many other games), and with their upcoming portable, if not too expensive, may go to compete directly against Switch 2.