The issue isn't so much how quickly we get the updates, more so just the level of importance for devices and lack of communication.
The one X has had 2 updates so far, which fix problems and improve certain areas that also apply to the other one series mobiles e.g. better accuracy for battery usage etc.
The S has plenty of issues as well, which could/may be fixed by a software patch e.g. the signal, wifi, multi-tasking issues (I haven't had a problem with them though, but many owners appear to be experiencing issues).
It isn't so much that they haven't released the updates, just more that they haven't announced anything at all apart from the usual replies like "we are looking into it" and "an update is coming".........no detail at all.
I am guessing the reason is because the device isn't popular at all really, many forums e.g. androidforums have hardly any threads/posts each day for the one S thread, very little interest in the developing community at XDA, think we only have like 1 or 2 guys working on CM 9, so HTC probably think why bother...... and of course the X being the flagship device so most of their time/money is going to be going into it
Maybe it is too early to say
But so far I am not impressed with the whole situation regarding communication, granted at least it doesn't seem to be as bad as google lately with the galaxy nexus and signal issues etc.