Temu built out some local distribution after it had already reached a pretty high level of popularity, but Temu was enabled by regulatory and political indifference that allowed China, with an enormous GDP, to get extremely subsidized postage rates. Also, lax enforcement of import duties (do you think the declared values were accurate?), and effectively zero enforcement of any safety standards, etc., on the products sold.

So, it was less of them following a path Amazon had trod and was maintaining, and more like sneaking in a back door and trying to sell you a counterfeit purse.

But if the US and EU had been on their game, it'd of either not happened or would've at least happened much more slowly.