I think that this (electing a Trump) is what happens when the pendulum gets pushed too far
Obama was more like the Republicans than they think. For example, he was fully behind the MIC, blowing people up without due process and so on. Obviously there is a big contrast, for example we know he did a lot of drone strikes because of his EO which gave us information on how many strikes were used and where, and Trump was doing about four times as many strikes per month when he rescinded that order so that we wouldn't know how many he's done since.
Even the ACA was a Republican health care plan, spruced up a little bit but still writing profit for insurance companies into the law. So no, the pendulum just wasn't pushed that far at all.
How can we get to a ranked-choice system at a national level?
Revolution. The chances of us rewriting the constitution for that (which is what it would take) are roughly nil otherwise.