Defensive? Let's see who they acquired:
- Dev studo focused on VR who has a lot of Evolution Studios and SCEE Liverpool former staff (Firesprite)
- Dev studo focused on VR who has more Evolution Studios and SCEE Liverpool former staff (Fabrik)
- Dev studio from Finland who after making many games for them just published their first AAA (Housemarque)
- Dev studio focused on remakes who previously worked many times for them (Blue Point)
- Dev studio focused on PC ports who previously worked many times for them (Nixxes)
- Dev studio focused on outsourcing who previously worked many times for them (Valkyrie)
- Top dev studio who revolutionized FPS, online MP and GaaS on console and created the top Halo and Destiny IPs who partnered with them just after leaving MS for Destiny 1 (Bungie)
- New dev studio with AAA devs who previously worked many times in top AAA IPs who partnered with them(Haven)
- Dev studio focused on mobile games who previous worked for them and generate them $1B/year (Lasengle)
MS bought a lot of very well known top multiplatform AAA IPs, tons of AAA dev teams and publishers.
Sony basically acquired people who partnered them for a while to support areas where they want to focus but pretty likely don't want their existing teams to focus on, or want to learn from these studios in these areas(remakes, ports, outosourcing, VR, FPS, GaaS). Regarding IPs, instead on buying a ton of super successful ones acquired very talented, experienced and successful teams experienced on creating very successful IPs.
One buys many top IPs and a lot of teams who made them. The other buys some dev teams who worked with them to expand to additional areas and talent with potential to create top IPs.
I think Sony will end buying a publisher with many IPs and popular teams, but until now I think their focus has been very different and didn't react to this. In any case, I think MS was the one reacting to Sony buying many important dev team and top (not dead) IPs because Sony had way more than them.
Like many other Japanese publishers they realized that the Japanese console has been shrinking and that doesn't make sense anymore to make small games targeting Japan only but instead to make bigger games with a global appeal. Kadokawa gave 2% of their stocks to Sony in exchange to help them bring their games and anime to a global market and to give them a more global approach.
Plus Sony owns the main channels (PlayStattion and Crunchyroll) where their products would be mostly sold in the west. And well, like From Software and several other game publishers and game developers owned by Kadokawa, Kadokawa themselves made dozens of PlayStation exclusives since the PS1 days.
The weird thing would be what Sony does with the non gaming and anime parts of Kadokawa? They have stuff like publishing labels for books, mangas or magazines. But Sony could do the same they did with Bungie: they can put them under SIE and let them work as they did until now, to allow them to conttinue with non-PS business in this case outide gaming.
I think 4-7B range is more for people lke Sega (around 4), or maybe even Capcom (around 7). Bandai Namco would be above 10B. Like Kadokawa, they also have the "issue" of their non gaming business, from arcade and pachinko stuff from toys in the case of Bandai or resorts in the case of Sega.