That's a strong point. At the same time, it cannot be argued that there aren't significant "spoilers" or schisms within both major parties right now! You are thinking of the big national races, the presidency with the electoral college and the Senate. But this does effect downticket races, the schisms. I.E., just now in Buffalo, many people who vote Dem did not like who the party picked to run for mayor, a radical, and they instead helped elect the primary loser by write-in vote, a moderate.

Likewise in VA, lots of political people are surprised that Youngkin won while not publicly courting Trump. Everyone was ruing that Trumpies have taken over the Republican party and nothing can be done about it, but that this shows that is not necessarily the case, that a different kind of Republican can win.

They are two supposed "big tent" parties that don't reflect the reality of their supposed electorate, they are people forced to be in the same party even though they disagree vehemently within that party.

That is why Bernie Sanders is still an Independent in the Senate, not a Democrat. He has not changed his designation there.

They're not real parties anymore, they're unified about very little.