Are dart sports mostly gone

I think that all of the Darts/Valiants/Dart Sports and Dusters are harder to find than they were 20 years ago. I used to see them in people's side yards or out in fields. I remember buying them for under $500 each years ago.
This year, I picked up a Dart Lite and a 4 door Dart...

3 Ds 3.JPG

I'm building the 4 door to be a quick cruiser with a 360 and an A-500 overdrive. The Dart Lite has no title and all the "Lite" parts are gone so it will be used as a stunt car for a video I'm planning.