I guess it depends on the niche. 3D printer parts do often pop up on Amazon 1-2 months after Ali for 5-10% extra. I think many sellers on Aliexpress are aware

I guess it depends on the niche. 3D printer parts do often pop up on Amazon 1-2 months after Ali for 5-10% extra. I think many sellers on Aliexpress are aware of the true price people are willing to pay and charge close to that. And then someone does the arbitrage on Amazon close to that. Now if you want to see a "real" good price, go to Taobao and cough up for the MOQ of 1000, that's 1/10th in my niche.