For me, VR bought me to ED.
I don't (well didn't?? ) consider myself a gamer. I upgraded my graphics bought a rift S last year to get into VR on a niche flight simulator that I fly. Once my rig was upgraded, I had that sim working and bought another basic sim from the Steam store. Whilst nosing around the steam store to see what this 'Steam 'thingy" was about, my eyes fell on ED. "I remember that!.. I used to play it o my BBC micro back in the '80s". It was on sale as well, and it supported VR... I purchased it... "Wow!!" within days I'd purchased Horizons as well, and have mainly played ED since (far, far more than the niche flight sim that I originally bought VR for).
I do recognise that VR in ED at the moment is a compromise in many areas, but the sheer immersion and situational awareness in the ship overrides those issues (just) and programs such as voice attack can paper over some of the cracks...
I do occasionally use 2D when I don't have time to set up my rig for VR, but that is just in separate short sessions for simple tasks.. things like flying a re-positioning flight without cargo (to set me up for my next VR session), or visiting an already unlocked Engineer, or purchasing/bulk outfitting a new ship.
ED without VR in the cockpit is unthinkable to me, and if VR is removed to turn ED into an FPS game, it will lose interest from me. Indeed even last night after seeing the mis-launch video and the realisation that VR would likely be the first casualty of "ED FPS mode", I was left wondering if the mining flight that I was about to embark on was worth it.. I'll carry on for the next few days until the situation clarifies, but I can feel my motivation slipping already.
If the devs have truly taken the decision to ditch VR, then It's almost certainly too late for any amount of lobbying to change that. Decisions will have been taken and work underaken that precludes reversing the decision.
Obviously without full information on the new update, it's difficult to make an informed decision now, but it's likely that if VR really is removed and there is not another yet unrevealed 'killer feature' in the expansion, motivation for me to play ED will diminish and I'd not buy the expansion at launch. As another poster mentioned above - Curiosity might see me purchase it in a deep sale a year or two down the line.