I still think exclusivity deals are a bit bogus to begin with, but I think a perfectly reasonable compromise is to be exclusive to a particular storefront, but not a particular device. If another device shows up with the right capabilities, and the community is willing to do the leg work to port my legitimately purchased game to it? Awesome! Rah rah community, you've just expanded my potential market considerably, for no effort on my part.
The only real advantage I can see for a developer to be exclusive to hardware at this point is to cut down on development costs in the first place. The hardware platforms are emerging, very different, and not always compatible, even if it seems like they would be on the surface. So I can understand the reservations against wanting to code for or support more than one complicated VR setup. But if anything, it's been shown that the VR community right now is chock full of enthusiasts and tech--savvy people who will happily take a stab at those sorts of complicated ports all on their own. I think it's important that they have the freedom to do just that.
If they need to sell 500 units of hardware or 5000 games to break even on a given investment, and selling that hardware also increases the odds that you'll purchase other exclusives from their store once you've sunk the cost, there's plenty of motivation to do it, even if you don't end up buying most of the exclusive games.
(Note that I am not weighing in on the ethics of this, just remarking that there is a legitimate business reason to do it.)