There is a key to the revenue stream for existing catalogs. You are right, most of us will not splurge to replace our entire collection by re-purchasing it all in MQA for full fare. However, if there were an nominal UPGRADE fee we might convert our entire catalog which would certainly be additional revenue for the Warner, Sony, et al. The logistics may be slightly challenging, but Apple was successful when they upgraded files to non DRM.

1: 808.6 Anniversary, 504, Sony ES Bluray player, Apple TV, Trinnov Altitude 32, 7200SEU l/r/c, plus for immersive audio
2: Theta Compli Blu, Apple TV, HD621, G61RSL, B&W Sig 8NT l/r/c, & Runco Plasma
3: 861v8, 504, Apple TV for streaming 3100 l/r/c
roon all around