What if Sonos disappeared?

No reason to panic yet. Even BlackBerry is still alive and (somehow) kicking, and look where they came from.
Sonos could easily survive losing their entire surround product range without any harsh effects on their overall sales numbers. Some new Play:x speakers would be nice though. Their advantage still is with the speaker's pristine sound quality compared to the majority of competition.

Bose - On third redesign in 4 years.
Denon - Second redesign in less time than Bose, promised multiple features that never arrived.
Apple - Airplay 1 a failure, just now using from-the-source streaming that Sonos debuted over a decade ago.
Samsung - Basically dead.
Bluesound - Niche product.
Yamaha - Third failure in a row for multi-room audio.
LG - Who knows?

Sonos - Best selling, best reviewed, most awarded, most selection, 1st with third party voice control.

I wouldn't worry about Sonos.

If they go completely dead I'd hope they'd publish the encryption keys and software source so folks could keep using and improving their Sonos systems.

Well the world would keep spinning for a start.

1st World problem (and a made up one at that) if ever I saw one.

Quite what "not catering for the latest and greatest audio formats" means I don't know. I wasn't aware that mp3 or AAC had been usurped by some hitherto unknown great format. Maybe the OP can edamucate us?

Bose - On third redesign in 4 years.
Denon - Second redesign in less time than Bose, promised multiple features that never arrived.
Apple - Airplay 1 a failure, just now using from-the-source streaming that Sonos debuted over a decade ago.
Samsung - Basically dead.
Bluesound - Niche product.
Yamaha - Third failure in a row for multi-room audio.
LG - Who knows?

Sonos - Best selling, best reviewed, most awarded, most selection, 1st with third party voice control.

I wouldn't worry about Sonos.

What is this third party voice control you speak of, pilgrim? 😛

Quite what "not catering for the latest and greatest audio formats" means I don't know. I wasn't aware that mp3 or AAC had been usurped by some hitherto unknown great format. Maybe the OP can edamucate us?

I imagine that the OP was referring to the Home Cinema audio formats that Sonos doesn't support with their Playbar and Playbase?

I agree, I think the Sonos Playbar and Playbase look like excellent products in terms of form factor & judging from their other speakers, excellent sound quality, but the connection options and range of home cinema audio formats they support makes them very limited for a home cinema enthusiast.

Granted, that's probably not the market that Sonos were targeting, but it's still a shame that these things aren't included.

Where is this conjecture coming from?

Regardless, Sonos is just too big to just completely disappear. If Sonos sales suddenly start plummeting for whatever reason, the brand would still have a lot of value. The company would surely be bought before they completely fade away.

Even if Sonos did go out of business surely we'd still be able to use the current controller/app to play our music, at least until it became unsupported due to not being upgraded?

And then there are other controller solutions such as Sonopad/Sonophone.

Even if Sonos did go out of business surely we'd still be able to use the current controller/app to play our music, at least until it became unsupported due to not being upgraded?

That is an interesting question. You could do a factory reset of all your Sonos gear and try to set it up again without an active Internet connection and see how that goes.

If the Sonos gear doesn't have to call back to the Sonos servers for any information to set up (after a factory-rest of all your devices and operate) then we'd be fine without Sonos being in business for listening to our music libraries. Streaming sources would depend on the sources continuing to support Sonos device access.

If a factory-reset system won't set up without a net connection, then having Sonos's servers available would be essential. Any glitch that that required the connection back to Sonos to resolve would be fatal.

For my family the risk of something going wrong is well offset by the ease of use and there would be much unhappiness if we had to switch to something else out there. For all the Sonos warts the other choices I've looked at are worse.

It would most likely be bought up should they get into difficulties. It's the market leader and has beaten off competition for over a decade.

I think you must have read of some layoffs at Sonos that was talked about last year at the same time that they were changing course to integrate voice technology to control Sonos. That is Alexa from Amazon.

The only other thing might be the very strong dollar that could hit some sales, but people jump in as soon as there is a discount as I did last December with 2 x Play 1's & a Sub when they discounted the normal price.

The biggest advantage with Sonos is its longevity. So while it may cost more than some others, units from 10 years ago are still supported via updates. At that time Logitech was their biggest competitor and it disappeared a few years later after Logitech pulled out.

Sonos supports virtually all of the streaming services and many more, which is a great advantage. I suppose they would switch off if the worst happened as they're going via Sonos servers.

But, don't worry. There will always be threats. That's business life.