Aside from the historically high demand for used -or any- bikes... Ti bikes were never mainstream, and always expensive. People who bought or buy Ti, know what they are getting. So they are less likely to "dump" their bike just to get rid of it.
Bargains are out there, but you have to be patient. Very patient.
Or you can get a brand new
Waltly frame built with custom geo for around $750 + shipping. Cool graphics extra. I've been tempted to use them to get a breakaway travel frame...