Very true. I've noticed the same thing myself. Chalk it up to better training on the part of the Brits. Or absorbing a lot more American tv than Americans absorb Brit tv.
American actors now do brilliant British accents; just check out all the David Hare plays that come to B’way with American actors playing Brits. The training for accents in both the USA and Great Britain has improved drastically over the last few decades. We’ve come a long way, baby since the days of Dick Van Dyke (Mary Poppins) and Laurence Olivier’s awful American accents!
Unfortunately, in my past actor days I was truly terrible at accents. No ear.
Nah, it just proves that American pronunciation is the easier, more natural and thus correct version, while RP Brit pronunciation is contrived, unnatural and more difficult, thus incorrect... /grin