Does anyone care that the city of Philadelphia was renamed Flavia by Emperor Vespasian in 69? [An interesting sidenote has Vespasian in Egypt in 70 where he had a vision at the Temple of Serapis. Temple laborers were convinced he possessed divine power and could work miracles. He left his son, Titus, to destroy Jerusalem and the Temple.]
Would be kinda funny for the writer of Revelation to write a letter to a city using the wrong address.
Additionally, Laodicea was mostly destroyed by an earthquake in 60-61, from which it never recovered. This also would be kinda funny for the writer to address a "lukewarm" pile of rubble as if nothing had happened.
Just a little historical context without any theological pretext.
If that happened, do you think the people of Philadelphia themselves EVER referred to their city (or their Church) using the middle name of the Emperor of Rome? I doubt it.
I'm sure that while the Roman Governor may have referred to Philadelphia as Flavia, the people in Philadelphia probably referred to the Emperor as Flatulence but I doubt he would have answered to that name.
I also doubt very seriously if Jesus would have used the Roman emperor's name in a letter praising the Church that had been named the "Church at Philadelphia" even before Flavius Vesparian came to power.
And now you have Laodicea being destroyed at least 5 years before the earliest date anyone has given to the Book of Revelation. I dare say that most cities in that area were largely destroyed by earthquakes every decade or so and rebuilt upon the same ground. That was the nature of building and architecture back then. A 5.0 earthquake which would do little damage today would do major damage to unreinforced concrete or unreinforced brick or stone buildings. I'd say that within 30 years of 61 AD Laodicea would have been largely rebuilt (and probably knocked down again a couple of times in the interim).