This isn't a super unusual markup. There's a huge amount of other costs which bring the overall margin down (e.g. even if you just looked at the markup retailers use you'd think everyone should be in retail or trying to bypass them, until you look into the cost of warehousing, warranty returns, unsold product, 'shrinkage', etc).

There are countless companies making USB/similar cables. They are a commodity and it's hard for them to stand out.

So I use brand (Anker, amazon basics, Apple, etc) and store (amazon.com, best buy, target, etc) to narrow down the countless cable options.

Those numbers are marginal costs only, the manufacturers also have substantial fixed costs. Anyhow, there already are lots and lots of USB cable brands, although I suppose many of them are just rebranding bulk cable products.

Thats a 95% gross margin, and in reality the manufacturer is not going to be selling at retail prices. A lot of the available margin is going to go to the retailer.