Suffice it to say that John’s tour guide drew John’s attention first to the Old Testament cradle of the redeemed (that is, the gates) and then to the New Testament fulfillment in Jesus Christ (that is, the foundations). It can simply be a matter of the gates being more obvious to John’s eyes than the ground-level foundations, and in a similar way the well-known beginnings of God’s redemptive work in Israel than the recent fulfillment in Jesus Christ. Though the question may be interesting, it has little value and generates only speculation.
14 And the wall of the city had twelve foundations, and on them were the twelve names of the twelve apostles of the Lamb.