Obnoxious British accents - Americans Can't Get Enough

Why is it that Americans have become so drawn, in this twilight of their empire, towards cockneyesque abrasive annoying British accents?  One hears it more and more, every day.  Time was, one would hear some rich, or even unaccented American tones, urging you to save lard, smoke Chesterfield, enjoy Roma sherry, try tough cuts of beef, and so forth.  But now, Americans seem to have made a firm compact by which they will not buy useless crap they’re going to have to throw away anyway, unless it comes along with a more-or-less fake adenoidal British accent.  What is the American love for this?  Why have Americans given over their late-night splice and dice ab machine mercials to fake-o British accents?