Totally agree...however, if they failed to allow people to pair non matching speakers with the Sonos OS...I cant see how they will do what youre asking....hopefully a third party app or add on witll allow thisIn the short term, it's not really going to be a problem for anyone. But what if, in 6 months time, Spotify for instance change some of their API/software meaning SONOS now need to update theirs to keep it all working. With my legacy speaker, I can't update. Or I do the update and chuck a Play 5 in the bin. It's ridiculous.
Just let the Play 5 be a slave in the system. It doesn't need to talk to Spotify (or another music service), it just needs to receive music from my "modern" speakers.