That's actually fairly common practice. It's called White Label - as in, print-your-own-brand. Think of a Chinese factory pushing out thousands of products without label, to be purchased by another companies who will, then, put their own brands and market the product. You can find both complete trash products to high-quality ones, and everything in between. Sometimes, a company will add a service to the product, creating a quasi-new product - like WyzeCam.
It seems that, if Anker used this method in the past, it's no longer doing it. I've been noticing the care in the design of Anker's latest products - sister brands included.
Of course, some times there's also just plain and simple imitation, design copies and fakes. Any time you see something that resembles a high-profile company with another brand, it'll be one of the three.