I got my Nikon 200-500mm tele lens off Amazon, and it was sold by Amazon. It was also, by its serial number, a gray-market item manufactured for the Chinese market, and not covered by warranty when sold in the US. But you can't find that out until you have it in your hands.

It worked perfectly as I got it, and the model had been on the market past the early peak of the bathtub curve, so I kept it. Still works perfectly today, too. But it taught me a valuable lesson about how far Amazon can be trusted on high-ticket items.

These days the only camera gear I get from Amazon is trivial niche stuff like eyepiece diopters that aren't worth anyone's trouble to gray-market or counterfeit. For everything else, there's my local camera store, or B&H or Adorama.