BA choose to let those with elite frequent flyer status have a wide choice of seats, even those who book close in (and pay higher fares), by making the non-elites pay.
Many other infrequent travellers (especially those on award tickets) may not like that and complain about it ad infinitum (often, ad nauseam), but I can entirely understand BA's priorities.
AA 77W business: nice cabin, but booking within a couple of weeks of travel, you will never get a window seat. That doesn't much happen on BA.