Apple compares better to Google for phone OS upgrades, than HTC or Samsung... for obvious reasons. They, the both of them, keep the upgrading to themselves as a "cost" of allowing the vendors to sell them. The HTC's and Samsungs of the world however, are beholden to the carriers (the carriers are their customers after all, far more than we are).
I don't think HTC is really trying to keep everyone out of their phone, though they put more effort into it than Samsung does. They have to keep appearances up with the ATTs of the world that they are trying, but make no mistake, if they REALLY wanted us to not unlock the phone, we would not.
Samsung is no saint when it comes to upgrades either. This is the first android phone I have owned that is NOT Samsung (Captivate SGS1 and VZ Gnex), and both of those had upgrade issues. Even the Gnex... and it was NOT Google with the problem on that, but VZ. Just like ATT is the problem here with the HOX JB update. I will agree that Samsung is putting their larger dev force up to keeping their devices updated, but I bet most of that is not dev work, but marketers massaging and making the carriers feel warm and fuzzy. As proven by the availability of JB software for the HOX in the custom world, it is NOT because the software does not exist. It is because ATT doesn't want to... deal with something. That something is debatable, be it support calls for upgrades that go sour, bloatware that works on new platform, or whatever the hell.
The only way to truly deal with timely upgrades is to get phones from the software maker's themselves... like the Nexus or iPhone. I sympathize with the rest of us, I really do... but getting upset at HTC over this is like kicking your dog because your cat pissed on the floor. Get mad at ATT, and get a Nexus next time or deal with the custom world. /rant