According to Sony and IDG last year PC and console mobile (the majority of the market, mostly GaaS) continues to grow while PC and console (markets where GaaS is dominant but as more more non-GaaS titles than mobile) remain somewhat flat.
Inside console, add-ons (so mostly GaaS) revenue keep growing and eating revenue from game sales (most top sellers are also GaaS). As GaaS, F2P and game subs keep growing on console, game sales decrease:
More recently, this year Sony mentioned that over half of the PSN store revenue comes from the top GaaS titles (maybe only the top 10):
Meaning, GaaS is dominating the market when looking at all platforms, when looking at consoles, or when looking at PS only. And their market share keeps growing at the expense of the non-GaaS games.
But if you look at the Sony SP non-GaaS titles, in most cases the most recent title of each studio (or almost) has been their best selling / fastest selling game ever:
- Japan Studio / Team Asobi: Astro Bot
- Arrowhead: Helldivers 2 (can be played as SP game even if mainly MP)
- MLB: the recent GaaS ones were mentioned to be way more successful than the previous ones, without mentioning details
- Insomniac: Spider-Man 2
- SSM: GoWR
- Bluepoint: GoWR
- Polyphony: GT7 (wasn't clear if the fastest selling of the series, but now also as the extra revenue from GaaS)
- Guerrilla: HFW was selling like their record game HZD until got included in PS+ too early as a test
- Housemarque: Returnal
- ND: TLOU2
- Bend: Days Gone
- Kojipro / Kojima: Death Stranding
So yes, in case of Sony SP own games they are selling better than ever (even more if you also count their late PC port), even if as a whole seems that non-GaaS SP game sales -or at least revenue- is decreasing. The problem is the improvement these SP games got in revenue/sales isn't as big -at all- than the increase in budget they need every generation (+ inflation).