That is the rosiest possible explanation. It seems far more likely that Verizon, understandably, didn't want to market a phone carrying the logo of a company that no longer sells phones. Once the acquisition of Nokia is complete, a Microsoft logo will be slapped on the 929 and it will see a late release. That's just my 2 cents.
Somehow I doubt it, the phones already have the Windows logo on them as one of the buttons and you might see that same logo on the back in the future, but I think the Nokia has to continue because people already associate it with phones, plus it was a huge name in the late 90s. The MS/Nokia marketing machine is already working well in 2013 and I think people are seeing the ads and thinking "Cool, Nokia is back in the game!". If Microsoft tried to tie the Microsoft name to it too much, people might rebel against it because it has, for a long time, been the hip thing to hate Microsoft thanks to the success of Apple and Google marketing propaganda (forget how Microsoft is entirely responsible for modern computing as we know it, gotta hate em cause Apple said so).
Whether it's called the Nokia Lumia or the Microsoft Lumia, the money is going to M$ either way, they will do whatever they think will be easier to market. Nokia as a word just sounds cool and exotic and I think they will have a far easier time marketing something as sexy sounding as 'Nokia Lumia' rather than involving the word Microsoft.
I think the real answer is that Verizon just doesn't just GAF because they already make so many sales with Android devices. They could take or leave Microsoft products and at this point they could take or leave Apple products as well, everyone is on the GS4 or HTC One bandwagon lately and Verizon seems like they enjoy milking the gravy train of those devices, probably because so many accessories are on the market for Samsung and HTC devices, Verizon sales team members are just told to push the accessories with the phones to increase profits. It's a lot harder to do that with these Nokia phones and I think that's why Verizon doesn't care that much.
I think what will happen is as WP gets more marketshare, Verizon will be way more eager to play ball, but it looks like AT&T is going to do need to do most of the legwork to help make WP a more popular platform in the US. This is my view anyway, it just makes the most sense to me, Verizon has always been "that company" that milks the status quo instead of trying to popularize new phones and devices themselves, AT&T always does that part and then Verizon hops on the bandwagon.
Personally? I am very very close to just leaving Verizon and grabbing a 1520 on AT&T. I'm off contract with grandfathered unlimited data, but I frankly barely use it because WiFi is everywhere and is way faster in most cases. I just want a powerful flagship WP device and Verizon is quickly making me lose patience.