The problem that so many people have with progress is that it is incremental, by definition.
Not necessarily. Often progress comes from the extremes. It doesn't necessarily come from the middle. Take gay rights. Yes, you had to wait for the political middle to make it to that point, but once it did, progress came rapidly. The same with women's suffrage, and the civil rights act. These were all causes pushed by the left, and once a big enough portion of the population was on board, the change was very sudden.
The problem right now is that there are a lot of issues where the centrist citizens of the country are on board, but even many democrats in congress are not. In my estimation, this country as a whole is much further left than our elected government. There are a lot of changes that have been building for years, that the citizens of the country support, but haven't been enacted. Most American's want to end Citizens United. Most Americans want universal healthcare. Most American's support cancelling student loan debt. Most Americans support stricter gun laws. Most Americans support mandatory paid parental leave. Most Americans support combating climate change.
The problem is, most of these things will cost the ultra wealthy money and power, and these are the two things they don't want to give up. The wealthy are going to continue to try to exert their disproportionate power to steer us either away from these types of policies, or at least so that we just kind of play around with them like what happened with the affordable care act. Yes, the affordable care act was an incremental improvement, but it still left the insurance agencies, health care agencies, and drug companies in positions of incredible power where they could continue to exert control. I think a lot of America is fed up with incremental change that leaves them falling continually farther behind. Personally, while we can argue about what led to Trump all day long, in my opinion that is the root cause, the reason he wasn't just laughed out of the primary in the first place.