Q. How did you arrive at what each of the churches in Revelation 2-3 represent, i.e. Catholic, mainline protestant, evangelicals, apostate, etc.? Also, why would the church of Smyrna not represent those Christians being martyred today?
A. One of the four accepted levels of application of the seven letters is prophetic, because taken in the order in which they appear in Revelation 2-3 they chronicle Church history.
There have been martyrs throughout the life of the Church, but the letter to Smyrna (Rev. 2:8-11) has symbolism that pertains specifically to the Jewish/Roman persecution of the Church which lasted through the reigns (days) of 10 Roman emperors. It ended when Christianity was made the official religion of the Roman Empire and was merged with the pagan Roman religion, symbolized in the letter to Pergamum which followed in Rev. 2:12-17.
NOTE: You can read all four levels of application of all seven letters of Rev. 2-3 here.