I don't think the left, or even the "establishment", is all one monolithic agent. I think there are different streams that all converged to the point where we're at.

One stream is the deep state, controlled by Washington DC insiders. This is the Hilary Clinton / Liz Cheney / MIC faction. They were threatened by Trump because A) he won when he shouldn't have; B) they weren't able to control him. This is the stream that is most able to carry out conspiratorial state-level actions against Trump, like the Russia Collusion Hoax.

The other stream I believe is the Obama / Silicon Valley/ Hollywood types. Let's call this stream the cultural elites. They are not necessarily DC insiders with great control over the state apparatus. But they have money and cultural power. They are primarily social liberals who are afraid of religious boogeymen, but more than anything they are just virtue signalers whose ultimate agenda is to A) have prestige among their peers and B) to influence policy favorably to their business interests. These people hate Trump mostly because it's cool to hate Trump, and saying anything good about Trump is a sure way to lose social prestige.

The third stream is the mainstream media, which itself has a lot of social, political, and economic connections to the other two streams. Because of these connections, the MSM was more than happy to take an activist stance against Trump, rather than simply report the truth. The MSM does have one dynamic not present in the above two, which is the need for ratings. Fearmongering begets ratings, so there was even more incentive to ratchet up the hysteria against Trump. Of course, the deep state and the cultural elite were more than happy to let the media do this, because it played to their interests.

But combine this together and you got a toxic brew of absolute Trump derangement syndrome, which likely is what led to the events of today. But I don't think it was all planned from the beginning. It's basically each of these streams doing what's convenient and good for themselves, which is culminating into the situation we're in now. Which may not actually be good for the Left because people are waking up to their toxic nonsense.