It probably has a lot to do with lowering the price point of shuttlecocks as well. One of the biggest barrier to entry is badminton's high cost to play, with shuttlecocks being the biggest culprit. With good quality feathers, there's very little room to cut costs - there are a lot of manual labor and testing that's required, since natural feather is brittle and random in quality. Synthetics, on the other hand, technically can be made and tested mostly by machines, which means economies of scale can kick in to lower the price of shuttlecocks in the long run. This, of course, is more in the interest of BWF, which I am assuming is a big proponent of this change, and possibly one of the catalysts for this movement.