What a strange thing to say. Whoever they were covering must have been pretty obscure because I had never heard the songs until Zeppelin recorded them. And the group had a unique sound that made them easily distinguishable from other groups which were popular at the time.
If you're looking for over-rated groups, I think you need to look elsewhere.
“Whoever they were covering must have been pretty obscure because I had never heard the songs until Zeppelin recorded them.”
Well, if you had white skin, sure they were obscure to you. Most of what they stole were songs by well established R&B artists, which is why they were able to pass them off to white kids without raising too many eyebrows. Though, they were equal opportunity thieves, stealing from folk singers, other rock bands, and even in a very prominent case from one of their early opening acts.
I don’t hold that their musicianship was overrated, but their “songwriting”? Certainly.
There used to be a four part series on youtube showing how nearly everything on I-IV was plagiarized, but BMG has taken some of those down, so here is an example of just 10 songs:
https://www.youtube.com/watch?v=tiiY4ciKFQA