Well, to some degree. Just not as massively... I would say that what happened is England stayed England, and we changed. Essentially, what you have in America is the remnants of hordes of foreigners attempting to pronounce the King/Queen's English. For awhile here, even up to the 1950's you had very small predominately single-origin communities. Out here we have a Dutch community that while it's been here for a long time speaks differently from it's neighbors who largely speak like the rest of the Chicago metro. But, around here you have a vast difference between the old south-siders (heavy Irish and Italian influences), the new south sider's (who are largely African-American, who sound like hip hop artists), and all of those people speak differently -- but live in a 40 mile radius.
If you go 60 miles south of town, the people start sounding like they came from Tennessee.
If you go north of the city, they sound like they came from New England. Needless to say, I always find this amusing. Anyway, it doesn't amaze me that America largely became so different than what we'd call British English. America isn't even the same with itself in 100 mile intervals.