This topic seems many years late. In the mid-2000's Sony had mobile games of GoW, Ratchet (2005), Loco Roco and Socom. They're released smartphone games before, including Fat Princess, LBP and Uncharted. And until recently, Playstation Japan had a mobile division.
I don't think Sony investing in the mobile department is now some cause for concern. Expanding their market into non-competitor markets is just good business, maybe. And a Wipeout mobile title suggests that a console version is likely in development if you ask me.
Just because Sony thrives on high-budget narrative experiences, doesn't mean that is all they produce. Destruction All-Stars, Sackboy and Returnal all very clearly do not fit into this category. And some of the partnerships they have announced (like with Haven and Firewalk) suggest MP-based experiences. As long as people are buying these Sony titles, then Sony will be fine. Ultimately, there are every few studios competing at the same level of high-budget narrative experience. Just look at the new GotG game: it looks potentially fun, but the narrative parts that have been shown off have been pretty bad. Comparing it to something like Uncharted is, so far before release, night and day.