Guys... These saws are all made by one Chinese company, they are not copied off of other Chinese saws, that would be ridiculous. Do a little research on your own, you may end up in alibaba.com or similar and you'll get a manufacturer name eventually, find their site, you'll see what I'm talking about. these guys will let you choose your own colour scheme and logo, including what to put on the bar ("MASSIVE 20" PULLER" that's what I'd choose! -- now that would sell!) and they'll happily stamp it on, inject whatever plastic in whatever colour you wanted, assemble it, put it in a container and send it to your local harbour assuming you wanted several 1000s of these.
There are several (but 2-3 main ones) engine manufacturers for chainsaws in China, same deal. Some companies will simply order the engines and assemble the chainsaws themselves. There are other companies that simply buy the parts, put a few screws together and resell.
You may end up paying 10 bucks for an oiler worm drive, the cost in china is $0.15 to the customer in medium quantities. Manufacturing costs are minimal specially for injected plastic in high volume.
Whether they began by copying an echo or not, that's up for debate. There are Chinese copies of Walbro carbs (also Zama) so that's not a surprise at all. They would rather copy something that works for them than having to deal with the R&D, which I still believe they suck on.
I'm willing to bet if you live in China and you consider yourself an engineer, you'll have on your CV something along the lines of "can copy anything". But can China even design a pair of underwear without having your balls pop out of the seams?