For my coworkers based in Taiwan who are somewhat fluent, they mostly don't recognize it, and really can't.

Their limitations are effectively hidden from them. Odd things still come out, but in informal contexts it's not worth correcting, and there's little opportunity for formal critique. (There's also the issue of "face" that complicates matters and drives me insane. It's easier with people who have spent a few years in the US, though.)

If there's no (near-)native speaker around to check, nobody's going to notice until it goes out to the world, and then there are a half billion people ready to jump on it.

If they recognized it, I don't think cost would be a factor. I could review/correct a site like this in an hour (or less). I might spend a day on the mini-manuals that come with some gadgets.

Absolutely. It is ungeileivable.