Check out your party's front runner, then come back and ask this question.
For all his faults, Donald Trump is far from an "extreme" conservative...
As for the OP, the Democrats have undeniably pretty much lost all of their cultural conservatives and social moderates, so in that regard, they absolutely have shifted left, and that's the reason why (Blue Dogs, moderates and such losing in 2010/2014). Now, what is ironic and kind of funny is that many White Southerners who complain about the Democrats becoming more liberal have only themselves to blame ... their presence in the party is what kept it closer to the cultural/social center from the 1970s/1980s on...
