Doubt that Sony isn't worried about Nintendo's massive success in these last few years and MS digging a foothold in the industry with Gamepass and the acquisitions they have been doing.Sony's game subs have been growing during years, they would continue growing without doing anything. But they'll add a base GP like tier available (unlike PS Now or xCloud) worldwide, plus include many content more (Bloomberg mentioned hundreds of games, witthout adding their own games day one but adding more newer games) to PS Now while improving pricing.
Plus they plan to expand PS Now to more countries and platforms. So they won't only retain it, will grow it. Plus as in a corportate level, not only for gaming, Sony is planning to boost their subscription service not only improving them and acquiring IP for them (plus companies who make them), they also plan them to push them with marketing. And well, in a year or two once they get rid of the chips issues game subs will skyrocket with skyrocketed console sales.
Regarding Sony's financials, their game subscriptions already generate almost $4B/year (and growing) and these improvements will help them grow faster. Regarding to their comparision with the MS or Nintendo ones, they are way smaller than the Sony ones, so Sony aren't worried about them.
But as for the rest, I guess we will see. These rumours makes it sound like Spartacus will be an underwhelming service, but it needs to be seen if they are true.