Trickle down economics, as a theory, has been around well over 100 years, and it's never been believed in by everybody. Hell, a presidential candidate gave a speech against the idea in 1896
You're correct about misinformation having been around forever, but access to and ease to create misinformation is greater than ever before thanks to the Internet.
IIRC two states and several major cities have also successfully implemented rank choice, and in every case it's been because of Democrats.
As more and more local governments make the change, it'll become more popular and gain more support on the national level.