The music industry does not want you to be able to own the music you stream, you only must be able listen to it. Ok so far.
Now we have the fact, that you can easily save the music you download. Basically you copy the record without buying it. Today I can crawl through the TIDAL Library and creating a copy of everything they got. Even the HiRes stuff, which is basically the master copy. Today I can copy and save all music I stream. Basically I get hold of the master copy.
The infrastructure established with MQA allows now to digitally sign and encrypt the music, so you can only play it in HiRes, if you got a matching device. This is only controlled so far today, that DAC manufacturers have their devices checked by MQA to comply with the license agreements. You as a consumer can copy the MQA file and play it on every MQA capable device. It sounds very similar as the master copy. But it is not the master copy anymore, it is a crippled format.
Now look 5 years into the future. MQA becomes widespread. Then, with the technology embedded in MQA, it is easily possible to apply short living certificates. In other words, you can play it on decent hardware for one week in HighRes. After that period you can only play it in LowRes or theoretically you can make it impossible to play it at all. Until you pay again.
This is the part where DRM comes into play. The existing infrastructure allows to establish something like pay per play. You do not simply pay a monthly fee. You also have to pay extra if you want to listen to the album Z of artist Y. Maybe it is also only something like you can own the file, but it is no better than an analog recording.
If you look at the patents of MQA, at license terms of MQA, everything is ready for this scenario. Maybe you have to do a firmware upgrade at some stage on some DACs, I don’t know.
But as soon as MQA got enough marketshare they can flip the coin. The tried to do it already several times. It never really worked. This is another approach.