I've got and old Rubik's brand and a Zhanchi.
Colour comparisons:
White - Zhanchi looks brighter than Rubik
Yellow - Zhanchi is a bit darker than Rubik
Green - Zhanchi is darker than Rubik
Blue - Zhanchi is darker than Rubik
Red - Zhanchi is darker than Rubik
Orange - Zhanchi looks darker than Rubik
The colours are slightly different. That could be to do with the ages of the cubes. But surely, not all the colours would be different. Can you copyright colours? If Seven Towns made better cubes, then it may be viable. If a competitor makes a better cube than yours, you wouldn't stop them making it, you would try and make a better cube. Why wouldn't they stop the production of the cube alltogether if they could? After using my Dayan Zhanchi, I wonder how I did a 34.7 on my Rubik.
Why do people always by a Rubik's first? If you can get a better cube for the same price, then get the better cube. If shops sold a better alternative to the Rubik's (not too much better, a beginner couldn't handle a Zhanchi) for the same price, what cube would they buy? Seven Towns should make better cubes and then more people would use their cube. Surely, they can design and make a better cube for the same price?
I think Lubix should take a storebought, mod it, lube it, re-sticker it (beware of the sticker colour) and maybe sell it, and send one to Rubik to give them ideas of how to improve their cube.