PBS has changed so drastically over the years. I remember when they had one or two fundraising episodes a year; now they seem to have them once a month or so. They used to be commercial free; now almost every show has a commercial sponsor. The only difference between PBS and network tv now is that PBS offers more quality programming, especially from the U.K.
I'm not at all surprised to learn that there's no legal reason the BBC shows couldn't be broadcast at the same times here and in the U.K. Just show them at non prime time network hours just as cable tv does. I will no longer contribute to PBS until they change that delayed policy. I, too, love Julian Fellowes.