Your example of 'usb cable' is a very good one for highlighting this problem. You are seeing so many brands because of an army of "Amazon Associates Sellers" / FBA - Fullfilled by Amazon Sellers ( I like to refer to them as scam artists) who identify various electronic gadgets, household items, and other things that are in demand, that are light (so cheap to ship) and that are available in bulk in Alibaba or Alibaba Express. They simply slap on their brand logo / name on packaging, pay a few select reviewers to do a 5-star review on amazon and make a whole bunch of sale.
So in essence, the chances are that these 10+ brands you are seeing for 'usb cable' are all sourcing the same exact 'Made in China' product from the same factory in China through Alibaba. Do a search for 'Strawberry corer' and you'll see what I mean :)
This is a very real problem that amazon has been very slow to resolve.
There are even Fiverr gigs that do the product research for cheap. Source: https://www.fiverr.com/gigs/amazon-fba