That point is a bit of a red herring. The question isn't the value of the update; it's whether existing customers should have to accept inferior terms of service to get it.

The right path for Sonos would be to open-source the kernel and hardware drivers, then either keep it up to date with a base feature set or budget $100K or so a year to run a bounty-based community contribution program. That will end the complaints that Sonos risked bricking hundreds of millions of dollars' worth of consumer hardware so its marketing department could harvest email addresses. Not everyone would like that choice, but it would be a better choice than the gradual decay of perfectly fine (and expensive) hardware that should otherwise last for decades.

Unfortunately the economics of service-oriented consumer hardware is all screwed up these days. Should buying a proprietary connected geegaw for a single up-front fee entitle me to eternal updates? In what non-pyramid-scheme economic model does that work? Yet in our world where we're still weaning ourselves from the dot-com years, that's typically the expectation.