Not 2020, no. But it is in their plans. I can't speak for FSX.
Maybe they could do something like how in Elite Dangerous you hold middle mouse button(? can't remember exactly what the control is) to freelook, but that's not as good as being able to control your PoV directly by moving your head.
There's more to immersion than stereoscopy. All the different elements of VR (3DOF tracking, positional tracking, 360 imaging, hand/controller tracking, stereoscopy) work together to flip a switch in your brain that tells it that you are in something rather than merely looking at something.
Even simply covering the entirely of your 360 range of view is enormous on it's own for flight sims. Think of the $$$ that sim enthusiasts spend on multi-monitor setups.
It tracks your actual head motion and exaggerates it (this can be tuned to your liking).
0: https://www.naturalpoint.com/trackir/trackir5/
It's a great little peripheral, and much more affordable than VR or a multi-monitor setup.
In a flight sim you have lots of dials in the cockpit you need to look at, and long viewing distances outside the window. None of the VR headsets I've tried have had good enough resolution to have a clear view on the cockpit instruments. The combination of cockpit very near and long viewing distances is also a bad recipe for motion sickness.
And then there's the controls. With a VR headset you can't see your hands or your controllers. With a hands on throttle and stick controller (HOTAS) you can fly around just fine, but when you need to toggle flaps or landing gear or navigation instruments, it's difficult to find the right button for that with a headset on.
So VR is ok for casual flying around, maybe even some dogfighting or aerobatics with simplified aircraft models. But once you need to deal with aircraft systems or navigation instruments, you're better off with triple screens and/or head tracking.
Is that not the case for flight sim setups? I can’t imagine looking at a horribly stretched image on a side window to be a nice experience.
Edge of screen mappings can be a little tricky but the higher level rendering engines can make near seamless transitions.
Military and commercial simulators try for displays that absolutely minimize visual artifact distractions so the experience is as close to sitting in the seat as possible.
Have you tried the Index? It used to be bad on the Vive, but Xplane with the Valve Index finally made it possible for me to see the instruments without squinting.