I think we mainly disagree on the why of this. I think it’s an inevitable outcome of our electoral system.
We have a system where there are only ever really two choices. Since it’s a zero-sum game, not voting or voting for someone other than the top 2 is giving a half vote to whoever you least want to win.
This means both candidates have to not appeal to the wings, but to the middle, because that is who could possibly flip. No socialist is voting for Trump. No Ayn Rand or whatever adherent is voting for Harris.
Thats why all our elections come down to a razor thin margin. Both parties have a pretty good idea of what is going to appeal to that middle, and they campaign on that. Why do you think Harris gushed about fracking?
So, to not cede the middle which is necessary to win to the other side, both parties end up very samey to try to appeal to them. They pick their pet issues (phrasing) to try and rile the base up, but at the end of the day you’re never going to see a huge difference between the parties in a two party system. And if you do it’ll be a blowout.