Yup, I remember when the purchase was announced, myself and many others thought, well that's the end of Oculus as we know it!
I owned the DK2 at the time, and was planning on getting one of the 'proper' released versions, but once the FB purchase was announced I decided not to bother, eventually getting a Steam/HTC Vive instead, more costly but arguable a more capable device (e.g. full 360, although lenses could have been a little better).
I also remember Oculus and FB announcing at purchase time they'd run Oculus independently, not interfere, and never integrate it with FB. Many including myself, didn't believe this at all, and we all know where that ended up!
I remember a while back someone doing a tear down of one of the newer Oculus models that came out after the FB purchase, and working out they were likely being sold at a loss. The assumption at the time seemed to be that they wanted to outsell the arguably better technically, but much more expensive (as in twice the price) Valve devices, especially the Index when that came out, and that FB would make up for the loss later my monetising the Oculus users more directly.
Such as shame, as the original Oculus company, seemed to be so forward thinking, and interesting.