There's the design but also more subtle dimensions like specific draw force profiles, materials and lamination combos, grip designs and riser weighting that all factor in also. I see many bowyers copying each other drag-and-drop there, but few complain about that, rather more the 'surface' aesthetics of the design in particular, elements that even in a bow don't actually impact anywhere near as much as other less visible variables.
In any case, a good shoot is a good shoot. If I can get quality for cheap, then I'm in. Perhaps I would've bought a clone instead of my massively overpriced Hoyt Buffalo back in the day, if I knew it shot as well. That said, I probably wouldn't feel as good about shooting a bow that was an effective copy, solely for aesthetic reasons.
The other thing is that designs can not be patented, only inventions can. A new kind of bow (atop recurve, longbow, compound etc) could be protected under IP, but not styles of that bow.