Meddeli is just one of the many production companies that manufactures go to have their products made cheaply to compete with the competition, (Previously it was Japan)
Yamaha, Roland, Korg etc. do not use all their own components but buy them off the shelf (Anybody can buy them) with just a few specialist parts.
The big manufactures sell and license their technology (Particularly the older technology) to other manufactures to use, so there is no need for them to copy and the big manufactures still make money from them.
This is not new and has been going on for well over 100 years, (China is just the latest place to make things cheaply) and applies not just to keyboards but virtually everything else.
Are their some rip offs, absolutely, but again this is not new. (You will not remember (As you probably weren’t born) but in the 60s & 70s Hong Kong was what China is today)
Manufactures putting their name on something cheaply made by a production company is (You guessed it) also nothing new, as it allows them to be sold in countries where income is small, (And people can’t afford big brands) however this has the psychological effect of imprinting the big brand names in their consciousness, so that when their economy improves they are already halfway hooked into brand names.
As I mentioned above, it applies to everything made today and in the past, which is how capitalism works.

Bill