What was stopping the British from taking their pelts directly across the Pacific? It can't have been American control of the region if this is the explanation for how America got control of the region.

Spain certainly wasn't exporting silver from the New World to Europe before shipping it on to China; they shipped it directly there.

That's a good question. The British were definitely engaging in a very, very lucrative trade in sea otter pelts from the NW Coast of British Columbia, trading direct to Macau, and the Boston Men/USA got in on that as well over time.

Plausibly some agency (Hudson Bay company?) had a monopoly on beaver trade and this did not apply to sea otter, or maybe the story isn't quite right or there were other economic reasons why beavers to Asia as a concept wasn't exploited.

I guess it depends on what you call the new world, but for what it's worth that's not quite correct, the main transit point was Manila.

In true pedantic HN fashion I am currently vacationing on the west coast of Mexico and learned this fact yesterday.