I understand that each port has a circuit-breaker which can be reset (by unplugging everything and powering it off and on again, or something like that).

EDIT: Apologies, it looks like they used to use fuses before they switched to resettable circuit breakers. Here's a Reddit post where somebody shares an (excellent IMHO) customer service email from Anker on the issue: https://m.reddit.com/r/perktv/comments/2fd00z/anker_dead_por...

Interestingly, I had exactly the same thing happen with an EasyAcc five port USB charger.

I wonder if Anker and EasyAcc use a common component on those products, one which is prone to this sort of failure.

One of the EasyAcc 5 port chargers looks literally identical to the Anker one. I suspect at least one of them is re-badging?

One of the things I noted recently is that I have purchased RAVPower, Aukey, Anker, and OMAKER products which all came in nearly an identical packaging style. I suspect many of them use the same products or same distribution vendor which whitelabels the products for them.

I used to notice this a lot more often for Anker, but their stuff seems to be diverging. I wonder if they bootstrapped from some of that stuff but have been moving more towards their own products.