A group that wants to privilege winners is more likely to win than a group that wants to privilege losers, for one thing.
I was shocked at how long it took Labour to beat the Tories in the the UK in the last decade. I mean the Tories kept screwing up over and over and it had to go really far before voters finally gave up on them.
It's easy to conclude that politics in the US are like professional wrestling and the Democrats are getting paid to lose.