One way they turn designs around so fast is by stealing from indie artists [0], [1]. [0] http://shoparttheft.com/ [1] http://www.cbc.ca/news/trending/zara-stealing-artist-1.36890...
This is why clothing is branded. You can make a T shirt with 'Hello World' on it and anyone can copy that, with a different font not even being necessary. However, if you don't go for the 'Hello World' and have your brand name on the T shirt then anyone copying it will have some lawyers to deal with (potentially). Therefore the only things you can sell in fashion retail that are not going to be blatantly ripped off a…
Commercial artist don't need validation. They are usually employed as artists as their day jobs and make art in other mediums for side projects. This is like windows including a cracked version of sublime text and saying well at least you know someone likes your work.