Move Upgrade to Provide Home THeater Support?

You seem to be unaware of Sonos speaker features. The Arc can connect to your sub, and to appropriate surround speakers, wirelessly. You can use two One’s or One SL’s (or one of each) for surround duty. They will not need an Ethernet cable. That would seem to be the solution you need. 
The only Bluetooth-capable Sonos speaker is the Move. Other than this, Bluetooth is only used during speaker setup. 
If you keep one or both Moves, then when it is on your home network you can group it/them with your Arc to have the same source playing to both.

Just a bit of an add on question. My ARC is wired to my router. So I know when I’m streaming music to the ARC, it then uses the 5ghz Sonos radios to blast the music to the other 3 speakers via wireless.

Question. If I’m watching a movie, the audio content is coming down the hdmi ARC channel. Does the ARC still use the 5ghz radio’s to communicate to the surrounds and sub? Or does it for some reason use WIFI in that case? I’m going to guess it always uses the 5ghz sonos network right?

Definitely all you need is POWER for the surrounds. They will communicate wireless for the audio. Failing that, you could always use some wired ceiling speakers ran back to a Sonos Amp. That is supported as well. In that case, you just need to get speaker wire to the location and run it back to somewhere where you can plug in the Sonos Amp and connect the speaker wire to that. The Sonos Amp will work on wifi. This will eventually be my setup. I have the ceiling speakers already from a Russound whole house audio installation. Just need to get the Sonos Amp.

Right.

I understand the Arc and Sub work for surround sound with the TV. My issue is the two Moves I purchased cannot be added to that surround sound system as rear speakers for a home theater system. My core question is, is it possible for Sonos to provide a software update that would allow the Move speakers to be incorporated into the surround sound TV system so that I can use them as rears or is this a hardware issue. 

The bluetooth point was less related and more expressing disappointment that the Move speakers also cannot be grouped together in bluetooth mode. If I knew the Sonos Moves couldn’t be used in the surround sound TV system and I wanted portable speakers with bluetooth capability, I would’ve purchased another brand of bluetooth speakers (e.g., two UE Megabooms, which allows bluetooth grouping). 

This is deliberate by Sonos.  A HT setup is meant to be (semi-) permanent and the Move isn’t - it is designed to move.  The surrounds have to be configured every time you take them away anf put them back - and re-Trueplayec if you use that. This won’t be ‘fixed’ because it isn’t broken.

For less than the price of two Moves you can buy two One SLs to work as surrounds and a single Move to take around indoors and out.  In other words, you could use the products for the purposes they were designed for.

I understand the explanation for why they did it this way, but per the forums a lot of people would like the ability I described and Sonos has previously provided software updates to allow enhanced capabilities. See the following link where Sonos updated software to permit two subwoofers as an example.  https://www.techhive.com/article/3600138/sonos-users-can-now-double-the-boom.html

Two One SL speakers will not work in my house as I do not have the ability to plug in wired speakers where needed, hence the desire for a battery powered surround sound rear speaker solution. Per the forums, there are quite a number of people in my predicament (i.e., without outlets / wiring to support wired surround sound) who would appreciate if Sonos added this feature. For those who want to save money and have a more stable system, they can opt for the wired One SLs, but I don’t see why Sonos wouldn’t consider allowing the Moves to function in a Home Theater setup at the option of the customer, particularly for a $400 speaker.

What still is not clear to me is if they are able to upgrade this feature via a software update or if there is hardware missing in the Move that would require Sonos to release a new speaker should they decide to accommodate battery powered surround sound.

In the case of enabling twin Subs the business case was obvious. I’m struggling to grasp the commercial argument for having a Move double up as a surround, potentially depriving Sonos of, say, incremental One SL sales. 

I should add that there is some flexibility in surround sound setup.  Sonos does allow you to configure speakers up to 10 ft, I think, behind the seating area.  That should allow you to find an acceptable power outlet?

I mean….for the price of the Moves, hire an electrician to put a few outlets where you want the speakers and use Ones instead. It’s not that difficult to pull a bit of wire for an outlet. There’s usually one within 10’ you can tap into. I bet it would be cheaper than the MOVES! And be a way better setup!