/genuine question, asides from the obvious of republicans adopting left policy, what would have to happen for another party switch to occur?

like, i know it happened once. wondering what circumstances and context brought that about and if that’s even a realistic framing to think about today’s world?

Frankly the people are the ones moving further to the right because the state does not educate them and regulate corporate power, transforming the public into a myopic panicked herd.

That's a slope, not an aisle

If there's so much appetite for a progressive/socialist party in the USA, how come there isn't one that gets a significant amount of financing and votes?

ultimately its the voters. we have primaries as well as general and remember congress is what can really change things. The last election shows voters felt we were not right enough at all levels.