A setup consisting of HomePods and HomePod minis where the HomePod could act as a sub as well as the main speaker and minis as satellites would let people setup a surround sound system without wires at a reasonable cost and with a lot less hassle.
I wonder if the issue is latency which would hurt the effect.
One uses either speaker wires for “dumb” speakers or power cords for “smart” ones. There is no escaping “wires” in this comparison. If you don't like wires, neither is an option.
And I would guess the odds of many living/TV rooms just happening to have power outlets in all of the places hypothetical HPs suitable for a true surround setup would need to be is not high…. going to nearly 0% if one wants a true ATMOS setup with several HPs on the ceiling. They all need power- either through power cords or speaker wire.
If one is unable to run speaker wire through walls/attic/basement to get them where you want speakers (often more “where there’s a will” vs. actually impossible) there are
many options to hide relatively thin speaker wire vs typically thicker power cords through some hollow baseboards or crown molding or even running it OUTSIDE the house from Receiver through buried speaker wire then bringing it back in where you want surround sound speakers.
If one wants to go all the way to true ATMOS, you have to get speakers
above the seating position. So that's either protruding (hypothetical) HP orbs (you think iPhone camera protrusion is less than ideal, wait until you have whole orbs on your ceiling) or you can install quality speakers fully flush in ceiling, even paint the grill to match your ceiling paint making them blend right in. Conceptually, Apple could make flat ceiling HP speakers so that one is not putting full HP orbs up there, but there's not even a hint of a rumor Apple is considering such a thing.
In general, the 3.0 setup up front: Left, Center, Right "dumb" speakers is easy because speaker wires simply run along one wall and behind a television placed in the middle. A true Center channel will already beat a HP setup for theater sound because it will mostly own the dialogue instead of attempting to faux create it from 2 stereo speakers left & right. If one wants to improve the faux dialogue from stereo HPs, the easiest option is to bring them closer together near the the TV... but then you are sacrificing the stereo separation. 3 speakers deliver ideal dialogue
AND ideal separation. There's no way to top that with TWO speakers. Your ears
will hear the difference.
Anyone mostly happy with front speakers only (the HP crowd now), could add a subwoofer up front for 3.1. That brings much improved bass into the mix without any wires running back through the room to try to deliver surround too. This is the ideal setup for those who cannot or will not run wires back from the receiver but still want to maximize the sound out front. There is no way to crank comparable bass from tiny little HP speakers or "dumb" (but small) speakers. Subs are generally biggest speaker for a physics reason. If you like big bass, you need that kind of big speaker in the mix. There is not even a hint of a rumor of a HP subwoofer in development.
There are home theater systems that nicely overcome the aesthetics/opinion "problem" of surround sound signal without wires from front to back by making the Sub a wireless receiver and to which one connects (usually) 2 surround speakers with wires. So that setup is 3.0 up front
wired and then a wireless send of sub + rear channel audio to a subwoofer generally put behind or beside the prime seating position (PSP). 2 speaker
wires run OUT of the sub to feed to surround sound speakers beside/behind the PSP to deliver the true surround sounds. Wires carefully run from sub this way to rear speakers are often easily hidden and out of sight from the PSP.
This can work very well for those who don't want a few wires to run from front to back of a room. And these have existed and been refined for
years.
Hypothetically, Apple could replicate HP home theater speakers like that last paragraph: HP Left, HP center, HP right up front, wireless HP sub behind/beside PSP and then HP Left & HP Right surround speakers beside/behind PSP. But again, there is not a single rumor about Apple having ANY interest in doing anything more than "as is" with stereo-only HPs.
Lastly, true ATMOS requires
overhead speakers. You need to run wires up there (attic?). Else, you need access to power up there for any kind of wireless ATMOS speakers.
There is no way around that. Marketing putting ATMOS on the box or in the online description of a speaker or soundbar that is not going to be overhead is only faux ATMOS. Faux ATMOS- like faux center channel sound- can sound better than nothing... but if you want to maximize audio for your ears, there's nothing like the real thing.
Again, visit ANY professional theater ANYWHERE in the world and see how many lean on 2 HPs down front vs. putting speakers all around the audience. You won't find ONE like that even though it would be so much cheaper and simpler for them to only use 2 HPs vs a true theater speaker setup. Why? Because the ears would easily know. If you want the same at home,
replicate their setups... which is just as impossible with either 2 HPs or any single Soundbar with ATMOS written on the box.
One More Thing: If you really want "smart" speakers over "dumb" ones anyway but you also really want true surround sound in the theater room, go Sonos or similar. They
already have what people are dreaming Apple would develop someday: fully refined wireless* speakers (*but power cords required) for surround sound configurations and bass units too. The software to make it all work
already "just works" and they work just as well with
Apple Music and
Airplay. The Siri "smarts(?)" of HPs is also built into your iDevices, your Mac and your AppleTV to utilize them like you use HP "smarts(?)". They can be put into
HomeKit rooms just like HPs too so you can tell Siri to "play whatever in _____ room" or "play whatever whole house" and they will blend right in with any HPs to do as you command. Sonos
already does ALL of this vs. waiting & hoping Apple might start going there someday.
And big bonus: Sonos is not walled garden, so they work with pretty much
every other source of audio too, including having AUX in for connections to audio stuff you can't connect to your TV (like all kinds of things without HDMI outputs). People wanting much more flexibility in the main theater room could go Sonos and move HPs to other rooms where they can play fantastic-sounding music in those rooms. And when you give the order for whole home, Sonos and HPs will sync right up together and play as one.