I think all the onerous spar inspections and SB441's have taken their toll. Quite a few have probably left the country and many probably just sit around. Most of the 690's I see advertised are the "high end 690's", with the spar replacement and -10 mods etc. I couldn't find a single 690 below $600K when I looked at Controller. That's a lot to splash on a 690, when another $100K will get you a Jetprop.
To be honest, a good 690B would really fit me better in many ways as it would fit into my hangar, whereas a Jetprop would have to live on the ramp. But the drop tanks are annoying on the 690's if you want Jetprop range, therefore I never really considered them. LR range is what I live for.