Originally Posted by Globaliser

This is the normal process, and I don't see anything unusual going on here.

Because today is Wednesday and your flight is on Saturday, today is the day on which the edited seat map is released. It's also the day on which the aircraft code shown to you will have changed from the generic code to the specific internal code for the configuration planned to operate your flight.

The window for buying an exit row seat closes 4 days before the flight. This is why you can no longer get the exit rows.