They have not been cagey. At all. They have been completely upfront. Literally: in the first announcement from last summer they spell out, up front in the video, that OneD&D is the name of the overall project, including a rules update with the integration of DnDBeyond and a VTT, and that the books themselves will simply be called D&D going forward, using the very successful 5e chassis.
The immediate confusion, such as it was (and I think it is very overstated) has been mostly coming from a few loud voices on forums like this who almost instantly insisted that this had to be a new edition, yadda yadda. And haven't stopped. I understand the historical context for this confusion. What I don't understand is that, despite having the project explained over and over, some folks have just seemed to dig in their heels and say "nope." I fully expect that twenty years down the road some folks will be sticking to that position even as 99% of players don't know what they are talking about.
So no, WotC have not refused to name it. The name will be "D&D." As they originally announced.
