Why the third party in US never prosper

Simple math? Did you never take a class onUS Government in highschool??

You've personally witnessed how the Democratic and Republican parties lead when in power with Trump and Biden. How is Biden "going to extremes"?

A third party would never be able to pass any legislation in Congress if the other parties oppose them. Also both parties put a ton of resources into the candidates they want elected. The third parties don’t have anywhere close to the same political infrastructure

There is no third party. Only 2 parties controlled by military industrial complex

Libertarian party is on the rise

The two parties are two wings of the same political elite. Smokes and mirrors.

I disagree that the parties are going to extremes… unless you mean both parties have moved to the right over the past few decades. But at any rate, as a third party-voter, here’s how I see it: there are significant bureaucratic hoops to jump and the hoops are controlled by the existing two parties. On a less formal level, the media rely on access to politicians and the parties, the parties also provide content and share personnel with the parties and various administrations. FOX, NBC news etc all rely on formal and informal connections to the two parties. Finally, the “spoiler effect” in the national election has a pretty big hold on people. Because most parties are not membership-parties in the US, voters are less tied to parties and so if you are a third party with a realistic expectation of “it will take many election cycles for us to build a solid coalition…” that seems like a tall order and so people naturally tend to think, maybe that New Democrat or Republican who sounds fresh won’t disappoint like the other ones. For a left-wing view of barriers to third parties, this is a good read… I think the history is useful, but I disagree with the conclusions here: https://jacobinmag.com/2016/11/bernie-sanders-democratic-labor-party-ackerman