Eh TBF Sega mostly crushed themselves that generation; they were way too reactionary, divided, and tried taking on a company with over 10x their money and resources head-on.
There was only one way that was going to end, sadly. But at least they're still making some kick-ass games (quite a few in fact).
Only issue here is that there's only so much Sony can do spending-wise to make that level of a purchase without taking out loans or mixing it up with stocks & cash (or maybe stock, cash & loans). At some point they just simply can't compete at that level; this MS/ACTI move is outside of their territory (without potentially jeopardizing their entire company financially, anyway).
Sony has to play to their strengths. Nintendo's not out reacting by making a ton of acquisitions, are they? And they're even smaller than Sony. If a company like Nintendo can carve enough of a niche to do their own thing, why can't Sony? If Sony "have" to respond to MS on this, then doesn't that just mean they don't have enough of an identity to play to their own strengths? Expecting a sudden major response from them would be too reactionary for them IMHO.
Again, Sony'll be fine. I'm sure they'll acquire a few other studios, but compared to companies like Microsoft buying power is not one of their major strengths. It's their narrative-driven single-player style games and their film/television properties, and how they can integrate them together. They also have it good right now with arguably the #1 superhero IP in film with Spiderman (sorry MCU fans), and look like they're building up some kind of shared universe between Spiderman & Marvel films/shows and their 1P superhero games.