They don't want to release toons that are disappointing. So they only release strong toons. They want people to buy these toons, they can't just give them us for free in the several stores, like they did with R1. So they stretch it. They can't sell all the expensive toons at once. People would start to think that all they think about is to milk us.
Also there are two years until the third movie, one year between the next spin-off. Some time to fill.
The praetorian guard will be here soon.