On he subject of why they stopped selling, I've heard from multiple sources that at least one driving reason for stopping selling them is all the confusion and hassle. Too many people purchased the option without ever understanding its use or limitations, like you couldn't add on days later on, that you were spending hundreds of $$ to save $10-20, etc.
I did so much research before buying mine. Like, I can't remember how I learned about the option, but I crunched the numbers and read helpful posts about it. So when I finally called Disney, after literally years of considering no expiration tickets and several price increases, I knew exactly what I was getting. And the CM still broke it down for me like I was a child (and really almost sold me on APs for four people).

Hopefully by the time we run out of visits, we'll be residents and passholders (husband's dream is to live in FL... something about less taxes blah blah blah).