For instance, the original drug would have been researched and produced after hard work by brand X, after a few months or years, brand Y would just borrow the formula with or without consent and start making its own.
Superhit movies in one language would attract the attention of some in the film industry to buy the rights, dub it and then release and make a profit instead of trying their hands in a new movie. As long as the original work is acknowledged or a royalty paid as agreed, I would say, it's fine.
But copying or doing a business in a manner that the first individual suffers in loss or turnover and profit should not be allowed as it would unethical.
On a more general note, we should learn from others mistakes also as we learn to use others success formulas.
These people can get temporary recognition but in long run, they are identified, secluded and do not get long-term success.
During examination also many people copy and exactly reproduce what their neighbors are writing on their respective copybooks though the examiner who is checking the copybook easily makes out the difference of the original writer and the one who is copying and accordingly allocates the marks to them.
In today's world with sophisticated software and other methods, copycats are easily identified and many times are being punished also.
Knowledge is power.
Such phases are purely short lived and once it is exposed, they are sure to get humiliation and ultimately they loose rapport in their profession.
Originality though it may not appear an attractive creation would attract many and such heroes would be regarded as the super masters.