> Both parties in America are bad, they know they cannot be replaced because of the two party system
Yes, the Democratic-Republicans and the Federalists know that they cannot be replaced because of the two party system. (Likewise, neither faces the threat of, if it fails to be replaced, being completely re-oriented in a political realignment.) It's not as if, currently, scholars disagree about whether the US is in its Sixth or Seventh Party system -- the two major parties are dominant, stable, and forever unchanging.
Do you think "political parties in America never change" is a steel man interpretation of my comment? I would suggest there is material difference between my statement "the parties have little electoral incentive to change" and your interpretation "they do not change". In my view, the latter is hyperbolic but reasonable, and the former is outright true. The parties would clearly not act as they do if people had other options to vote for.
Yes, the Democratic-Republicans and the Federalists know that they cannot be replaced because of the two party system. (Likewise, neither faces the threat of, if it fails to be replaced, being completely re-oriented in a political realignment.) It's not as if, currently, scholars disagree about whether the US is in its Sixth or Seventh Party system -- the two major parties are dominant, stable, and forever unchanging.