From Achilles in the thread, page 6:
We will not reduce the royalties from 50% to 30% instantly. Instead, we will reduce it in separate stages, with 5-10% per decrease, depending on several factors. The most important one is that we will monitor the revenue paid to most photographers (overall and average) and will proceed with the changes only when these parameters increase, probably on a month to month basis.
So I understand they will make this first step and, according to what happens, they may even stop there. It's no guarantee, but it's a second chance. It is still a significant reduction (up to 20%), but we will see.