No, that's like saying that Ford would violate Audi's trade dress if they combine slim headlights flush with the body, a large front grill in trapezoid shape with the logo on top, and two air intakes at the bottom edges. It would.
That's all design is: a combination of functional and aesthetic choices, that lead to a particular look.
Silver wasn't very popular until not long ago. Black was the default, and still is for many manufacturers. It is also currently possible to make the frame even thinner, or non-existent. The choice to make it that thick (and black) shows that it's not about technical limits or 'evolution'. You can absolutely make a computer that doesn't look like an iMac; in fact everybody has been doing it for years.
Indeed, there was a huge production of so-called beige PCs, and nobody complained that they looked the same, since they looked like crap, and people wouldn't purposedly copy crap, now would they? The fact is that Apple products look gorgeous, and they want to keep it that way. Commoditization of that style would destroy its value completely.
That is, unless they keep leading the pack in design innovation, instead of trying to protect their old productions, and milk their fan base out of recycled ideas.
That's all design is: a combination of functional and aesthetic choices, that lead to a particular look.
Silver wasn't very popular until not long ago. Black was the default, and still is for many manufacturers. It is also currently possible to make the frame even thinner, or non-existent. The choice to make it that thick (and black) shows that it's not about technical limits or 'evolution'. You can absolutely make a computer that doesn't look like an iMac; in fact everybody has been doing it for years.