Tracking woudn't likely delay the release, it would definitely delay it, and would result in fdev trying to code for both a flatscreen Half-Life Alyx, and a VR Half-Life Alyx, with entirely different control systems.
But what I still don't think you see is your own proposal would "likely end up causing further delays" to the release. You still seem to think it's just flick the VR switch for VR headlook. I'll bet it isn't.
The existing game - in cockpit/srv - have VR, it's likely simple for EDO to just continue the same way. Basically no changes. But the first person additions are completely new, and it would appear
were not planned/designed/coded for VR.
Changing it now on the hoof? Its how IT projects end up a mess.
Not that I've been involved in IT disasters

no siree...