The fuck are you talking about? They did show up for Gore. He won the popular vote. The only reason Bush won was due to the electoral college flipping the vote. Gore’s election was stolen from him.

Democrats have not been moving left. They have consistently been moving further and further right since post-WW2 and McCarthyism completely demolished any legitimate left wing politics in this country. Meanwhile the voting population became more and more disenfranchised by the fucked up system we live under.