Even if there was some natural physical law that guaranteed that oppressive nations would eventually be overthrown/atrophy, there's definitely nothing that puts a bound on how long that will take.

And, as we've seen with Ukraine, war can break out more quickly than any of us think.

(also, if the social justice warriors in the West have their way, the US government itself would be overthrown and replaced with its own, authoritarian, but ineffective regime, long before a conflict with China would occur)

The summer of 2020 was a great preview of what this dictatorship will look like once the USD collapses in value another 30-40%. Burning buildings and more statues of "heroes" like George Floyd, who stood up to White Supremacy. Remember, removing "master" from git repos was done because of the legacy of slavery in the United States.