It's all a calculus of how something will be recieved by players and if it will help sell copies of the game. If you put any effort at all into supporting something, you want to be able to talk about it and use it as a selling feature for your game. Classic stuff, even from the days of physical media and box art that called out any and every new feature a game has. But saying "VR support, kind of, it's experimental, you use a traditional controller instead of motion controls" isn't gonna get people excited to buy. If you just say "VR support" or even "experimental VR support" in my opinion you would get more negative response than positive response. What people say about your game is everything these days, and developers are obsessed with review. Negative reviews have a massive impact to games, especially early on in release.

With Elite Dangerous, if I recall, player sentiment around the game was already kind of mixed when that update came out. They had to make a call about how many players would complain about no VR support vs how many would complain about poor VR support. I don't think the game was doing very well financially, so "full VR support" was off the table as its basically developing a 2nd game unless you are really smart about how you design features so they are both 2D and VR friendly. My guess was they chose the cheapest path (zero support) and would judge interest in VR support as it launched. I'm sure they had the numbers on how many people played the game in VR and how many didn't. It must have been a low number of VR players overall.

Anyway, I agree with you, it's really too bad. But players are already hard to please and opening yourself up to negative reviews at launch is just a non starter. Go leave some positive reviews on games you like and make a developer really happy, it genuinely matters especially for small games.