>By voting for either party we are essentially enabling the either-or system to continue

I used to agree, but the parties have no ideology attached to them. Their names are just generic terms regarding democracy and you can see how much their platforms have changed and moved over the last century. At this point they are just the Urban and Rural divisions of our election playoff.

They are just the ideology of the people elected. If you change the candidates of the party, you have changed the ideology of the party. Trump figured this out and instead of sticking with the Reform party, he just took over the Republican nomination.