@BRicardo In summary, some things look promising, but we just don’t know enough yet and history shows that we’re not going to get enough information from companies about the audio possibilities and workarounds until enthusiasts like us get our hands on the consoles.
Some things to keep in mind...
Optical Out can only send two channels (stereo) out in uncompressed PCM; for surround, your next device would need to be able to decode a Dolby Digital Live bitstream, and be able to process a binaural headphone surround mix from that bitstream (So, it would need to have a DSP function, DAC function, and either a built-in or separate amp).
When Xbox and PlayStation released their slim consoles, they both dropped the optical port. Xbox also never supported generic stereo USB Audio support, so users of that console were even worse off than PlayStation (which does support USB Stereo). The Pro/X models still had Optical, but hopefully the console makers don’t see the connection as a dying standard. If they cut the optical port, current DSP devices that rely on optical could continue to be used if you have a breakout box that takes HDMI-in and has HDMI-out and Optical-out, or if you have a TV that has an optical output built-in (My Panasonic has this, also supporting Dolby bitstream passthrough, love it).
However, both consoles (and particularly Sony) have included discussion of 3D Audio and headphones/headsets, so maybe they will have better support in the next generation. However, this is not a guarantee, as the PS4/XBO generation also touted TrueAudio 3D and Sphere audio respectively, and virtually no titles took advantage of it (Thief is the only one I know used TrueAudio 3D on PC computers with the same graphics card used in the PS4, and while the game supported headphone surround I don’t know if it used a lesser 3D processing codec, and at any rate I got bored of the game and never finished it). There were a few games that had their own binaural headphone surround built-in (and these worked great with gener, notably the Battlefield series and The Last Of Us, but it wasn’t widespread. The Bluetooth-streamed inexpensive audio from the controllers in the current generation held back the potential sound quality significantly, so hopefully the consoles will support binaural processing internally and then allow third party devices to connect via USB or optical. As a mainstream device, a game console isn’t going to have specialized components and design that enthusiasts are willing to spend in the aftermarket (like a DAC/Amp that costs as much as the whole console, or more!), so supporting third-party devices would be a nice compromise.
HDMI Headphone Surround processors currently are reeeeeeeeeaally rare and require a substantial investment, but if optical is dropped we might finally see some gaming accessories companies support this niche. There is a bit of a “which came first, the chicken or the egg?” question with 3D Audio: is there enough demand for the feature? Will 3D audio catch on if it’s actually widely available?
I have a Sony PSVR, and it has pretty fantastic full-3D audio (including above and below, not restricted to a number of speaker “channels”). VR is probably the best way right now to experience full, live, immersive 3D audio, but at least on the PSVR you have to use the (much better than the controller) DAC/amp built in-line with the VR headset cable. Something with the impedance of the HD 58X but the sensitivity and angled drivers of the HD 599/PC37X would be ideal in this situation.
We will just have to see what the future holds ¯\_(ツ)_/¯