In all seriousness, he likely ws very derivative in many ways, and no doubt he didn't come up with all of it himself, either - even today, travelling theatre companies will improvise, refine and work on their material collectively, and what Shakespeare wrote down was the result of those efforts. I suspect he was pretty good at the Elizabethan equivalent of PR are marketing, too.

But there's nothing wrong with any of that - he was a product of his time, just as anything written today draws on countless other works.