Are we talking about the same Logic Pro? https://support.apple.com/en-us/HT203718 shows quite a lot of activity of the last 2 years. Idk what you consider a "meaningful core upgrade".
Those are just releases that improve/change some small workflow stuff, fix bugs, or add minor or niche features like "Spatial Audio mixing with Dolby Atmos" that Apple cares about more than most producers do. The change lists look huge, but if you lose closer its all minor stuff.
The last release with a meaningful core update was 10.5 (May 2020) - the one that introduced Live Loops, major new devices like the new sampler, etc.
If it was a regular company selling its software, 10.5 would have been a paid update/major new version, and 10.6 and 10.7 would have been point updates.
It's nice, but I wouldn't go that far. Professionals who mix for Dolby Atmos do it with a Dolby-approved system, not their Atmos-certified home theater or Airpods Pro. For the prosumer market, it's mostly a gimmick to promote Apple Music.
It's not necessarily a bad playback platform, but neither is an Xbox with 5.1 surround hooked up. Apple's commitment to surround sound is far from revolutionary.
