Though I believe homage does qualify after a considerable amount of time has passed, and I do not consider a decade such a considerable amount of time.
According to my knowledge there is not a sharp definition of the borderline between "borrowing" something and obvious plagiarism.
Allow me to invoke a later example. As a film you had "Star Wars" and as a rival follow up TV series "Battlestar Galactica" (which resulted in an inconclusive lawsuit between 20th Century Fox and Universal).
The whole look of BSG looked like a clone of SW (no wonder, many of the behind the scenes artists of SW worked on BSG) but
the entire story premise was totally different than SW.
So I don't really see that much plagiarism at the expense of SW.
On the other hand you have "Forbidden Planet" and as a follow up TV series you had "Star Trek".
The problem I see here is that Roddenberry did
copy the story premise, i.e. a United (Federation of) Planets cruiser on patrol duty, and the basic plot element (what happens if man becomes like God?).
On behalf of ST and Gene Roddenberry I nevertheless have to admit that he turned a mediocre concept into something better and superior.
As a TV series "Forbidden Planet" would have sucked: The character of J.J. Abrams...pardon...Adams was hilarious. The captain always reacted to events, was hesitant and even made fun of in the story (with the doctor being the actual hero). Roddenberry was also correct that the character of the chef was rather redundant, both as a comic relief and as a member on an otherwise fully automated ship.
But despite my love for TOS, I don't think I confuse "inspiration" with "plagiarism". I'm pretty certain that without "Forbidden Planet" the Star Trek we know would have turned out quite different - if ever...