I’m not sure the impact of both can be really compared in terms of people playing it. If it had been on PS+ I’d agree with you though.
Although interestingly it was added to PSNow right when the GP deal ended (so it’s more recent) and only for six months.
Generally these games bounce around from subscription service to subscription service. It was also part of humble choice recently.
If you see a 3rd party game on a subscription service you can bet your bottom dollar it will end up on another one at done point. Some of these publishers are whores.
The general point is that the game has been available for cheaper than the price of a direct purchase on all platforms now, it's past presence on a particular service doesn't necessarily correlate with a potential future lack of sales on that platform, especially when the game is essentially being rereleased with new features.
With the exception of it's presence on PC subscriptions, the fact that it's previously been available on these subscription services doesn't result in a permanent place in people's libraries. Therefore the only way for someone who doesn't already own the game on PS5 or Xbox Series consoles to experience the new update is via a purchase of some sort.
It's getting to the point now where we are frequently seeing similar sales splits, even with games that have never been present on any subscription services. The "gamepass" excuse is not always valid, especially not here.