I don't think it will ever be back.
My husband and I went to WDW the very first month it was offered in September. Our
travel agent told us that disney was trying to fill up September and October, as they were slow travel periods due to kids back to school and to the high heat and humidity in September. So, they started the DP.
However, when we arrived that Sept. the parks were full of kids. I guess that taking the kids out of school with only 2 weeks in didn't bother some, and they wanted to take advantage of the DP. Can't blame them because it did save them a lot of money on food. We were both very surprised at the amount of people at WDW at that time!.
I guess it worked to increase the numbers, and they kept it up for quite a while. Now they have way too many guests willing to pay their high prices, so there is no need to do this to increase the numbers anymore.
That's the way I understand it started, as a way to increase guests at slow times of the year. Disney is no longer "slow" and they have an abundance of guests, so I'm betting there will be no DP again.