Can Forums be set so that the Start Date of a thread shows in the general information ...
Not without a hack to the vbulletin software which we lease. Whenever you see a resurrected thread, the person first posting to the ancient thread had to consciously acknowledge that the thread was old and press an "I am aware that this is an old thread" type of button to continue with posting. Tyme installed that hack as it was felt necessary to try
to prevent the type of thing you have observed.
Personally, I simply have made it a habit to look at the dates of posts when reading them or responding to them. Seems to work well, for me at least. (I also don't go scrounging around in the bottom of the archive barrel for a subject similar to the one I want to post about. But that's just me, I guess.)