I think you're being hyper critical at this point and going out of your way to look for reasons to bash HTC. They have plenty of problems, we all know what they are, but updates aren't one of em.
Does it really matter if they're only a couple weeks behind Nexus devices? Ask Samsung owners, or most others if they'd trade places with HTC in that department.
I'm looking for consistently not missing updates. The commitment is important, not so much the length of time. There's literally no reason every OEM can't release security updates the same day as the Nexus devices - they just have to make it a priority. But it's not just about security updates, the major version updates are important too. Launching with the newest version is good and an obvious move, but how long will the devices be update and how long after the release of N will it be for it to be rolled out to the 10, M9 and M8?
This isn't about tearing something down, it's about justifying one device over another. If I want a better physical design (not aesthetically, but usability) (also, obviously IMO), then I'm going to get a different device. If I want better software, I'm obviously getting a different device. If I want more up to date and more secure devices, that's not this. If I want the best screen, battery life, camera, etc, etc... right now all of the priority categories are being won by other devices. So one thing the G5 is teaching us is that your components don't mean anything if all they are is ringing spec sheet bells. Execution and being worth more than the sum of your parts is what matters. The M7 had that and it had differentiation and it made a lot of fans.
So far what I'm seeing on the M10 is a lack of attention to intention and what I need to hear from them is how they're fixing the mistakes of the last couple of years, why they're choosing to sabotage the physical design (in favor of what) and details of their plan to commit to timely updates to this phone, the last two generations, etc. Because as of today, the only two players in 2016 so far are Nexus and Samsung. HTC needs to prove something, we have no obligation to give them the benefit of the doubt. Marketing can't fix their trail of blunders. It's time to put up or shut up. I'm not going to assume they wanted to do the right thing and failed or that they don't know why these decisions matter. This is their hail mary and if they don't have a strategy, then it doesn't matter if it lands or flies low. So criticism is the default state until they prove it wrong. And I hope they do, but they've got two years of history to undo and it'll take more than two years to prove they've changed.