Of course the kingdom is all of ours. But only Peter has the keys. In the same way, I might say..."Here...you all have this vacation home. But I'm giving Silverlings the keys".
No, your idea is more like a father buying his son a new home but he'll keep the keys. You give a person property, you give him the keys. What's the point of an evangelical making a person a disciple as commanded by the great commission, then have to say, oh well, now I have to run it by Peter? Does not make sense.
Just out of curiosity, just what do you think these keys are? What does the bible say they are? Obviously they are not literal keys, so what are they?