Historically the churches in Revelation 2 and 3 were churches present in John's day.
“…What thou seest, write in a book, and send it unto the seven churches which are in Asia; unto Ephesus, and unto Smyrna, and unto Pergamos, and unto Thyatira, and unto Sardis, and unto Philadelphia, and unto Laodicea.” (Revelation 1:11)
“Write the things which thou hast seen, (the vision of the Glorified Lord Jesus - Rev 1) and the things which are (the seven churches in Asia - Rev 2 & 3), and the things which shall be hereafter; (Rev 4 - 22)” (Revelation 1:19)
Doctrinally they are representative of various churches in any age.
Spiritually the represent the church age from the early church to the present day.