There is a lot to unpack there.
So PSVR sales in the 3 million range as of August 2018 (or 85 million ps4 owners). So yeah; almost certainly more 4k owners. Not sure how the ratio of PS4 pro vs PS4 og lies with PSVR owners. I'd bet it skews heavily towards pro (if you can afford[1] PSVR you can probably afford the pro upgrade). Src:
https://gamingbolt.com/playstation-...nits-skyrim-vr-is-the-most-played-ps-vr-title
HDR is a different matter. There are a lot of HDR TVs, but quite a lot are not standard.
Anyway; as for the 4k part; it would be a nice upgrade, but a lot of '4k' games are not really 4k;
https://www.extremetech.com/gaming/235274-how-sonys-playstation-4-pro-does-4k-without-delivering-4k
Personally I think you are correct; we are not going to see PSVR support on the PS4. What drives me up the wall is that Frontier won't come out and say it. If the answer is 'no', I'd be disappointed when they announced it, but I'll get over it and move on with my life. Instead we are in the stupid limbo land of 'probably not' but we are keeping your hopes up. Frontier really needs to learn to say "no, we aren't doing that" (or even "not at this time") instead of being super vague about everything. Maybe there is some behind the scenes reason why (sony contracts/agreements come to mind) they can't give an answer, but they do it for other features too.
Of course the rumours about PSVR being a first class feature of the PS5; maybe there lies some of the complexity to the story. /me wonders if Frontier have ps5 kits and if Elite: Dangerous is coming to the PS5.
But I'd love a HDR patch too.
[1] Afford/choose to spend, et al