Given its backwards compatibility on a large number of players it only need be adopted as the main format by the likes of Tidal, spotify, Napster and the downloadable media outlets to get widespread adoption.
I believe you are missing one key point. Widespread adoption will only come when music labels provide "current content" along with the SOS that has been made available to the audiophile user on Hi-Rez sites. Sure we need the likes of Tidal to adopt MQA but first they need lots of "authenticated" titles.