Sonos are not intended to be powered down but left on 24x7. They automatically enter a low power mode when idle.

Since the currently playing data is stored on the speaker it will be lost if powered down.

I accept that normally one does not power down the speakers, however, we do get power cuts from time to time and there are occasions when it is necessary to switch off circuits at the consumer unit.  

The station is held in volatile memory, which doesn’t survive a power off.  In order to resume the station on power up, it would need to be written to non-volatile memory periodically and then read in upon power up.  But non-volatile memory only has a certain limit (~100k or so for older Sonos devices) of write/erase cycles before starting to deteriorate, and constantly writing out the station info would soon reach that limit. So Sonos chooses to favor unit reliability/longevity over the convenience of having stations/cues survive a power outage. 

Given all the “lost functionality” with the new app and updates, such as slower response time, lag in setting volume, and general usability issues that come with having all activities relayed to “the cloud”, certainly, it’s possible to store this data in “the cloud” along with everything else. Seems like a missed opportunity to address a common complaint.

Gaaaahhh! I want "my" Sonos back. If we have to have a cloud at least make it optional so my system works for local music with no required access to some remote machine.

I will admit that if we have to have the cloud there is a lot of stuff that could be stored there that would be nice, stations as mentioned, plus all the other stuff that is only in transient memory on the players due to write cycle considerations.