Fair enough, but I don't totally agree.
The Nexus may not get boomsound, since part of that is software. It may, or may not have the superior audio codecs. I wouldn't be surprised either way honesty. HTC may want to withhold that, or Google may pressure them to include it so that Google can market the sound. That being said, I wouldn't be surprised to see a HTC made Nexus that is very similar to the HTC 10. I imagine the design language, etc will be similar. It is more cost effect to stick with the manufacturing ability already in place. I think it is highly, highly likely we see a HTC Nexus with an obvious HTC design, and thus similar build quality. Why else would Google be turning to HTC?
The HTC Nexus will match the HTC 10 in hardware, minus the audio maybe, and possibly surpass it in some area.
The Nexus 6 was a great phone....but the Nexus 6p was better. It had a better screen, more premium materials, a better camera, and better hardware all around. It had the best possible processor available at the time, and honestly it was the only phone to manage the 810's thermal problems. The 6p was/is superior to the 6, and it had a lower price point.
Simply, the Nexus 6p was arguably the best phone made last year, and the price was reasonable. If Google release $700+ phone as the starting price, I imagine sales will suffer. I doubt google will make the same mistake twice, and I doubt the phone will be a bust (however it is you define that).