Most things in life is innovation, once in a while we get invention.
To do innovation, sometimes you have to reflect to the past, for history is a good and reliable source of knowledge.
So "replica, homage, recycle" designs are OK in my eyes. Outright fake (you use somebody else's brand) is a NO NO to me, other than that everything is OK.
In fact in business, there is such thing as "benchmarking" i.e. taking the best practice and apply it to our organisation. And what's the best and most economical practice other than "copying" a better management practice?
Maybe I'm a bit extreme in this regard, but maybe I'm extreme in nature
ps: in my biz, a lot of people copy my designs, i don't give a damn, as long as they don't use my brand. i believe it's my duty to improve and move 2 steps ahead of the copycats.