In a hypothetical situation, if satoshi ever comes back, does he has the power to kill crypotcurrency?
YES.
Let's say he comes back and says
"Okay guys, we're upgrading to Bitcoin 2.0.
This new digital currency has worked out all the bugs found in Bitcoin and is infinitely more efficient and has all these new features not seen in currency before.
Time to upgrade!"
Then everyone will switch over.
DUHHHHHHHHHHH
By your reasoning , if Bill Gates launches a new operating system , you really think everybody will switch to "Doors 8"?
More likely people will start arguing about the new features and about why he had come back and promote this.
Lots will see cia and nsa involvement with his re appearance.