Just to add to the discussion, it's interesting to consider this from a real life designer's point of view. One of my favourite knitting designers, Kate Davis, offered one of her first patterns,
owls, as a free download when she first released it. Debenhams then released a jumper for sale that was almost identical. I think the blog posts about it have mainly been deleted, but it was very difficult for her to pursue any legal action due to being unable to demonstrate any financial loss. Copyright law can be tricky to get your head around, but when you start thinking about it in terms of a real person having their design 'stolen', it makes more sense, to me at least.
Also, the Kate Davis' story had
a happy ending, as Debenhams made a donation of £5,000 to Chest, Heart, and Stroke Scotland, which was a cause very close to her.
That said, it is much more difficult to sympathise when we are talking about older OOP patterns, not to mention that it would be impossible to not draw inspiration from fashion designers and and ready to wear collections (amongst very many other things) - I want to sound clever here and add a quote about there being no truly original ideas/ production in the world but I can't remember it!