>>17999187the yearly fee is very intelligent.
Most people will only care about the bank when a new game is released in order to transfer.
And GameFreak releases a new game every year.
So the next games will probably be released a few days/months after the year of the first influx of payments end, an influx that will start when this free trial is over. Loyal fans will not feel the need to unsuscribe to bank. And this will surely be the only way of transfer from now on.
This also explains why they delayed Pokébank in the west, it is possible that future games will not be released simultaneously, so they added an extra timeframe.