OK, here's what I've concluded/deduced (I have the same problem as you, and in fact, went to the Sprint store yesterday and had the exact same experience as you!):
There is a wiki at
http://www.htcwiki.com/thread/104507...lt+WiFi?t=anon
regarding wi-fi on a different HTC phone, but with the same issues. My conclusion/guess is that the Mogul/Titan/Whatever has this same issue - something in the way the wi-fi is designed on it (software or hardware, not sure) is incompatible with some standard, possibly Cisco CCX. From what I can tell, CCX came out about three or four years ago. I have an older router, and so I fired it up and my Mogul wi-fi connected just fine. But on the brand new Belkin routers (actually, two of them), sometimes it would see them, sometimes not. It connected once, but that's it. I also tried shutting off SSID, deleting the profile, changing the security, and setting no security, but none of those work. I can connect at Panera, McDonalds, Barnes and Noble, work, but not with those brand new Belkin routers.
All in all, it's very perplexing that I've read about this problem in about five places now, but absolutely no one has a conclusvie answer. HTC should have been all over this.