Agreed. I bought an HTC Vision in part because Cyanogen mentioned that he had bought one and liked it, and I figured that this would make support a bit more likely.
However, there is still no official CM v9 build for this device. Andromadus is the closest to the CM experience as there is, but is moving along slowly. I think one of the issues is that the modding community has essentially become fragmented by the large number of phones - when there were only a few phones the effort to keep them supported as long as possible was MUCH more concentrated.
A further complication is that the more prolific developers tend to get new phones very often funded by donations. That tends to mean that much of the development effort gets focused on the latest and greatest phones.
Obviously the free software developers don't owe anybody anything - the community benefits from whatever work they donate to the cause. However, these sorts of factors make it unlikely that any new phone is going to have the support that the HTC Dream originally enjoyed (I hear you can get ICS for it), despite the huge hardware limitations on the Dream (a bit of a hacker's target as a result - plus just about all the devs have one lying around).
The Nexus phones by far have the best official support, however you'll only get ~18 months of releases if you buy one the day they come out. Since Google sells them until a new one comes out and they seem to come out about annually, if you happen to buy one the day before the next one is announced you will be lucky to get updates for a year. The downside to the Nexus phones is that they tend to be unsubsidized - though that can vary by carrier.