I'm surprised that it comes as such a surprise to so many. During the ABK era, many assumed that Sony should buy Square Enix or Kadokawa. Kadokawa always made more sense because they have a broad range of media. Until now, Kadokawa didn't want to sell, but that seems to have changed. To be honest, Sony and Kadokawa have often worked together in Japan and produced anime exclusively for Crunchyroll, and SIE also works closely with From Software and owns shares.
After the Paramount takeover didn't work out, it was clear that Sony would continue to sound out the market. The only question that remains is whether they want to take over Kadokawa completely or just parts of it. Sony didn't want everything from Paramount either, which is why the deal fell through (in my opinion, fortunately). If Sony doesn't get Kadokawa either, the next (but more expensive) step would probably be to buy Bandai Namco, which also has a broad range of media in Japan. But Sony has to invest profits somehow, otherwise they will be reduced by rising inflation and currency losses. Perhaps the current economic situation in Japan is the decisive reason for Kadokawa to now consider a takeover, and Sony is certainly the preferred buyer over Tencent or the Saudis.