Practically there is a lot of great content out there in 5.1 format, and the speaker setup for this is relatively affordable and practical. Atmos needs an insane number of speakers and the trick where they fake the height channel by bouncing it off the ceiling doesn't work everywhere: my main A/V room has a cathedral ceiling for instance.
I'm not sure that the object-based model is really right for music, many of the best surround mixes for music aren't about putting an instrument in a particular place as much as they are about starting with a 2 channel mix and adding ambience. A lot of what is special about sound in space is the way sound reflects off things and and a 5.1 mix can greatly improve and literally "put you in the world's greatest concert halls".
Also Atmos is being pushed for substandard environments such as headphones, smart speakers, etc. I just don't believe Atmos rendered on headphones is going sound as good as a 2-channel mix for headphones.