I agree with roo-bruce. Sonos tried to walk back their disastrous roll out of this news back in January, but all they really did was pretend they had reconsidered screwing over their users. Sonos cares not one bit about their customers or dealers. They care about one thing: Money.
No business can survive on thin air. Yes, you need to support your existing customers, but the only way you can continue to do that is to keep selling new products.
Sonos products are still great, but the truth is they've been held back by being first to market, and whilst they can sell to existing customers looking to expand their systems, it is getting more difficult to compete with other systems for entirely new ones.
They need to be able to offer new features, and that means a new architecture. On the other hand, they are the only manufacturer that has a defined minimum support for discontinued products. They are still allowing you to use the existing software on supported hardware, and it will continue to be supported as best they can.
The fuss being made over this is rather excessive when it's pretty much impossible to buy a mobile phone that has more than 2 years of support before being turned into a virtual paperweight despite costing 2x - 3x more than a Sonos device.