I think the answer to that is simply that they know. They know that they have successfully overtaken the schools, the church, the media, much of the government, the entertainment world. They know that despite their domination in all of these areas, and their ability to totally control the message and indoctrinate the young that the year 2010 was the high water mark of the American communist insurgency. They know this because they have seen that Generation Z and the younger generations are rebelling hard against the status quo as all young people do at some point, but that the status quo has become defined by the communist indoctrination, and the pendulum has begun to swing the other way. They know at some level this rebellion is deeper than the usual teen "phase" because the more they poke, the more they young find the entire foundation of what they have been taught is rotten utterly to the core.
They know that they are increasingly met with ridicule by their own peers. They know that Trump is not a rogue anomaly but the portent of a new epoch. They know the global backlash against multi-culturalism, and against progressivism is a broader reflection of this trend. They know they are stronger today than they will be again, and that if they fail now they will fall in the dustbin of history, and that the new history books will recognize communism as the failed ideology that it is. At least that's the way I see it.
I agree. It's not all Trump, but he is a bit of a bellwether. Although the Leftists say the opposite, I think they recognize that he is a smart. competent leader who will make big changes and make this country visibly better. The people elected him. The people want him. And he will have great success. And the Leftist ideology will never recover from that. It's basically over for them. Their calls for open revolution at this point is simply a Hail Mary because they are on the wrong side of history and they know it.