I don't think there's any way the 20's will be like they were. People used to cash out their points to get the site hits (which is where the 20's came from), but it's so hard to get points at Blink anymore that it's no wonder less people are able to do it.
Personally, I quit Blink several months ago. It was taking me just short of forever to earn a $5 Amazon gift cert, so it just wasn't worth it anymore...
I don't know about the Blink 20's, but I managed to get 270 bonus points today from the 4 "slot machines!" I got a bonus on each one--150, 10, 10, 100. That hasn't happened in a while!