I believe the context of what Jesus said here was about the question Peter answered correctly, not Peter himself.
“Peter, who do you say that I Am?”
“Thou art the Christ, the Son of the Living God”.
THAT is what the ‘church’ is founded upon. Not the guy who answered the question.
For one thing, if that is so, Jesus himself ‘appointed’ him. Today, these guys are nothing more than polititians like obama. THAT is how they get the job of Pope now.