Hollywood, the mainstream media and the public school system are all almost entirely controlled by people and groups friendly to the Democrat Party. Yet and still, even with that almost overwhelming advantage, Democrats can't do any better than a rough parity with the Republicans. If the tables were turned and the GOP controlled what you see on TV, in the news and what your kids are taught at school the same way the Democrats do, the Republican Party would win every presidential election and would permanently maintain unassailable majorities in Congress.
So, why aren't the Democrats running away with every election? Because selling Democrat policies is like Coca-Cola's marketing team trying to sell the public on rat spit in a bottle. Since they can't sell their product, they spend all their time convincing the public that the little Republican girls down the street selling lemonade probably spit in it when their mothers aren't looking. Sadly, this tactic works pretty well and a lot of Democrats end up voting for people who are ruining their lives.
1) Black Americans: Over the last few decades, no group has been more fiercely loyal to the Democrats than black Americans. Typically, the Democrats capture 90% of the black vote nationwide. However, it's worth asking what black Americans actually get out of that deal. Sure, if you're Jesse Jackson, Al Sharpton or Touré, it's a pretty good gig, but how does the average black American benefit from voting for the Democrats? Affirmative Action? That program helps very few people and it also leads to many black Americans getting into a college that they wouldn't normally qualify for with their academic record. Some people might call that a plus, but as a practical matter, it causes an inordinate number of the brightest, most promising young black Americans to flunk out of college when they could have graduated had they gone to less challenging schools.
In return for that dubious bit of "help," the Democrats fight voucher programs that could get black students out of failing schools, laugh at black Americans who are Christian, pro-life and believe in God's definition of marriage and they do nothing of consequence to tackle the crime and drug problems that makes life so unbearable for many black Americans. The worst places in our country for black Americans to live are inevitably run by Democrats who've long since given up on improving the lives of their constituents.