And I would say how does that compare with the pre-flood?Is it really that fast? I think this is just an example of some investment, no magic at all. Apple Music mostly bans algorithmic content and while some has slipped through, they do remove it as soon as they find it, I've seen it happen. I can't find a recent source on exactly how many Atmos tracks are on Apple Music, but it's definitely in the low to mid single digit thousands of albums, or tens of thousands of songs. How many albums in total are released per year? Hard to be sure, but it's for sure more than 100,000.
So, being conservative, that's only 1% of all music being produced each year that's in Atmos.
You are looking at this wrong. Have you been a consumer of surround mixes previously? Do you have a sense of what the landscape was like for fans of surround music?
The rest of what you wrote is more speculation.