It's an exclusive licensing agreement between Sonos (the biggest player in the multi-room WiFi speaker game) and Spotify. It's not that they are 'dumb' or anything else like that, it's down to commercial licensing. Sonos will protect the agreements / approaches they have, see the current Sonos vs Heos lawsuit...
Over time the exclusivities will disappear, don't worry, there's too many people at the door of Spotify / Tidal / Deezer / Pandora / Apple etc etc. But it will take time as it always does.
This industry is not getting cheaper and cheaper, we're simply convincing ourselves that we have to push the cheapest option to customers. #makesonosgreatagain
