It sucks to lose access to digital content on the original console, but I am at least glad that they are continuing to offer access to digital Xbox 360 games/DLC that are backwards compatible on Series X, and that folks can still download content they own.
This is akin to Steam declaring that it will no longer support Windows 7. Which is actually happening at the end of this year.
I agree, posts like this are more of a heads up. It was nice of MS to support Xbox 360 for this long anyways, it’s almost 18 years old now.