Currently, this is not supported.

If the USB-C is wired only for charging, this is not “some software business”. Besides that, “software business” could not be as easy as you think it is….

I would be surprised USB is only wired to charging functions. I would see the port being used by Sonos for troubleshooting.

Rearly? Dream on.

Now with the Era 100 & 300 which do have this as a feature, will the Roam also get this feature? 

If it were capable, you'd think Sonos would do it by now; if only to sell more $20 adapters.  The fact they aren't enabling this feature in order to pick up adapter sales from nowhere should tell you it isn't capable.

Yes, and the USB C port on the Era speakers can’t be used for powering the device, only data input (ethernet or audio).  The chances that Roam and Era speakers are using the same hardware for USB is very unlikely.

Certainly the fact that it doesn’t is a good indication that there is some hardware differences in the electronics inside of the different devices. If it were merely a software change, you’d think it would be already done. 

This is not true at all, the usb c is a geneal usb-c but sonos deactivated stuff ,

i am someone that ry things out and the usb-c clearly do data to because a powered eth 100/1000mbit works , the roam is seen on lan cable instead wifi, even the app reconize it ,so charging only is false

let me show you some proof

simple  a dock 

Not all nic chipset works, but some of them do, and i bet the usb-c is just a normal cominucation port without power delivery

Except we know it has power delivery, because you can power the Roam via the USB connection.

Thats charging, power delivery is power the devices via the usb port,

that is what it don't do ,

sonos is pretty smart by using ancient hardware,

because connecting a nic on usb-c on sonos it have to be rtl8125 if im correct,

the once that work so far on my era100 and most likely roams to are

Amazon Basics

Jsaux HB0603

Tccmebius TCC-S20C

the once that dont work

Anker 556

Ugreen 15727

Tccmebius TCC-S30C

Jsaux HB1201

i can not test the non powered nics on the roams since i have no breakout usb-c cable to externally power the nics,

but yeah sonos support is verry limited, witch is sad, 

i had to go eth because no mather what the wifi is to disturbed here even if i place my sonos 20 cm aside the wifi ap it still cutout on stereo mode, the sonos wifi generally is the worst kind i have ever faced for a premium pricetag, it might do well on places where nor many people live but not in a flat of 13x5 households, sonos is realy wonky although it do sound ok ,

i myself got a sub g3, 2 roams 2 era100, if the roams could act as back speakers it would be great for quadrophonic, what we used in the 90’s what now is called 4.0ch,

4.1 would be nice to since i don't care for center speakers

i myself have serval hubs and docks, so i always try various stuff, 

and maby roams also have aux in , but the problem is where do we find a powered aux in adapter, they don't exists,