Why don't they record in ‘surround stereo’?

Fascinating comments above. I guess another huge obstacle is all the Cable connections would have to be increased coming out of the back of the components if you expand from two channel listening to more channels. Vastly complicating the cabling and connectivity issues of the components.

If you have a good speaker system and great amplification, I guess the benefits are marginal. But there did seem to be openness in comments that there is potential it could be actually better.
 

Because I have nice speakers and amplification, including lots of tubes, I tend to listen to my home theater with two main speakers, eliminate the center channel and leave in the surround rear speakers . Often times this is a lot better. But other times you need the center speaker so the dialogue is more discernible and doesn't disrupt what's going on in the main speakers. This configuration can be handled toggling back-and-forth between two settings settings on the home theater remote. Ie. Super easy to go back-and-forth.

So at least on the home theater side I have the flexibility and it is working out really well

Try 5.1 SACDs.

Besides your AVR can send matrixed channels to the rears so what's your malfunction?

For a, moment I thought kota1 was back.

There are now hundreds of Dolby Atmos remixes of classic stereo recordings. It’s not generally understood that Atmos is a superset of Dolby Digital 5.1, and Atmos content will be automatically down mixed with no loss of fidelity to 5.1 if the AVR does not support Atmos.

My setup is: AppleTV 4K -> HDMI -> Marantz AV8003 pre/pro -> Marantz MM8003 power amp -> 5.1 speakers. This receiver dates back to 2010, long before Atmos, but the AppleTV automatically sends discrete, uncompressed 5.1 channel PCM to the AVR. Sure enough, the Atmos mixes play back perfectly in 5.1 surround, and are quite different than the 2-channel mixes. And there are hundreds of titles in Apple Music in Atmos format ... some new, some going back to the late Sixties, like The Doors.

True, the quality of the mixes vary, as it always has for surround sound. Some are very much better than the stereo release, and others are gimmicky and not very good. But most are an improvement on the stereo version, which are only a few clicks away if you prefer that.

Apple Music lets you choose tracks in several formats: 44.1/16 CD resolution in stereo, 96/24 resolution in stereo, and Dolby Atmos, which appears on the faceplate of the receiver as 5.1 PCM Discrete (not Dolby Digital). Based on the display, it is the AppleTV, not the receiver, that is decoding the Atmos stream and converting it to uncompressed PCM streams.

@lynn_olson 

Yeah I mostly see uncompressed PCM which my NAD processor calls ‘Direct’ and that’s mostly what I see these days. And I’m fine with that.

YouTube videos with music tend to be better in stereo as it mangles things when some of the signal flows through the center speaker at times. A lot of the music through YouTube is pretty darn good. That’s interesting Apple allows you to change formats but I’ve never drifted into Appleland. Unfortunately roon does not do that as far as I know. Or maybe it does in some of their DSP crap which I tend to stay away from.