So, on Origins and Generations, here's some speculation:
With the decline of the Pokémon anime's viewership in Japan among the primary demographic (as children are primarily watchingYo-Kai Watch), the anime has undergone a massive shift in direction. The attempts at more serious stories with character development that we saw in Kalos have been completely abandoned (with many believing that is why the writers from the BW arc were called back, and why Ash lost, something so negatively received even in Japan that the writers apparently apologized for it on Twitter). This is most clear with the new art style, which has undergone an astounding shift (and entirely for the worse, in my opinion).
At the same time, the older fans outside the target demographic overall responded very well to the Kalos arc (until the end), and Origins as well. Currently, Generations is scheduled for one episode a week until the end of the year.
The current speculation is that Generations is a test run to see how this style will work and be received. If it does well, it's expected to be the precursor to a second anime that will run concurrently with the one starring Ash, aimed towards the older and more serious fans.
Please keep in mind that this is mostly speculation, with no official word on the subject.
EDIT: Also, apparently Generations is a Western release only. Which is very unusual for the series, which has typically focused on Japan first.