You're Canadian, right? If so, I can understand that impression, because you grew up in a parliamentary political culture.
But here in the US, it's different, and the Republican Party will never die. The horror of the two-party duopoly is too deep. They'll never dip below ~35% of the national vote or ~45% of political seats. And when they come close they'll immediately shift their platform, start hypocritically raging against policies/actions they once did and accusing Democrats of doing them, and they'll rebound to become the party in power again within three to four terms.
I think it's possible, if not likely, that, before the two of us leave Sherdog, the GOP will become the "we need to observe institutional norms and procedures to protect the competence of our government" party (to keep Democrats from appointing [competent] judges at a rate even half of what they have done these past two years) and the "we need transparency and bipartisanship" party (to keep Democrats from furthering [actual good faith] policy even in a way exponentially more transparent and bipartisan than the Republicans' attempts these past two years). And it will work, both politically and electorally: the Democrats will wilt and the electorate will reward the GOP for it.