No, it’s not a myth. If you buy only name brand from authorized distributors, you’re fine.
For USB chargers, I stick to Apple and Anker. (And the ones included with Logitech gear.) DO NOT buy Apple, Samsung chargers on Amazon, eBay, etc, as they’re likely to be fake. But if you get one at e.g. Best Buy, BH Photo, etc. it’ll be genuine.
For most other things, Mean Well is a great value.