Sony are expanding SSM + GG, have expanded Sucker Punch earlier in the gen, created a new studio in San Diego, while smaller teams like Pixel Opus & Sony Bend are growing as a team + developers. Studios like Sony Japan and Naughty Dog work on multiple projects at a time (even if its pre - production in ND's case). Not to mention, Sony has created a bunch of heavy hitters this gen (GOW, UC, Horizon, TLOU2) that can move hardware next gen. Considering the studios they closed down/ reduced at the start of the gen, growth of their in house talent, PS3 games (GT6, Puppeteer, GOW: Acension, TLOU) that could have been PS4 launch titles, and the current pipeline, their out - put on the PS4 has been amazing. PS5 is going to be 10x better.
With that said, I do expect Sony to purchase a few developers in the next couple of years, especially since they are gearing up for PSVR on PS5.