Based on all the other, many threads about this, no. It was a restriction placed by Apple that Sonos had to accede to, as the Sonos doesn’t ‘play’ music on the controller. 

I can’t speak to the current state of BOSE, back when I did use them, they ‘played’ on the iOS device, and sent the music to the speaker. 

The Bose speaker can start playing music also by it’s own buttons or remote. When I do that and start the app later, I am still able to control the volume of the speaker with the iPhone buttons, although the music is definitively not played by the app.

Isn’t it, that there is a fee, if the app developer want to use the hardware buttons and Sonos doesn’t want to pay that?

Which Bose speaker?

Bose SoundTouch 20 Series II.

Should request Sonos support Dynamic Island. Not exactly the same as phone button controls but ime almost as good while adding other features.
 

You could put an IKEA hardware remote in your main living areas, super convenient and way faster and no bugs compared to the Sonos app. 

​@mensa This app has not been updated in three years (in the Apple app store)? Apple might have missed this. Lucky for Bose customers.

Better if Sonos would have done the same

But thanks, that could be the reason.