The democrats get beat the fuck out every time they run conservative. They plummet in popularity if they get elected and then betray their constituents by doing what the republicans want. Republicans will never elect a republican-lite when the real thing is right there.
Meanwhile left policy polls overwhelmingly well among everyone, especially people who actually might vote democrat, and it’s even more popular once people start feeling its effects, as you can observe in any country that has free or near-free healthcare and public housing.
Sorry, Juan Guaido already declared himself interim head diplomat for Europe. The best development agency in the world has given him 98 million to help.