They aren't running out of ideas as much as people aren't very accepting to new ideas. A lot of good things flop theatrically or get canceled early because people like what is familiar. They also love simplicity. Look at all of the reality shows. It seems the majority of people like to sit back, relax, and turn their brain off instead of having to put too much thought into what they are watching.
I love reboots and sequels. It's always nice to step back into a world you enjoyed as well as see fresh or updated interpretations of an older film or TV show. Sure, it doesn't always work out, but that's usually the business side interfering with the creative.
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Long Live the New Flesh