How do those who believe that salvation cannot be lost interpret Revelation 3:14-22?

The resolution is found in recognizing that Jesus is delivering warnings that are both collective and individual. At the individual level were true believers who had lost zeal and been distracted by wealth and pride as well as unbelievers who were causing problems. The believers were warned that they would be disciplined strongly if they did not repent. If they repented quickly and sincerely, then they would be able to keep their church. Otherwise they would become individual believers cut off from fellowship, which causes suffering and impairs spiritual growth and health. Their church would lose its lampstand.

What happened in real life? At the council of Laodicea in 363-364 AD, the church of Laodicea rejected the book of Revelation as worthy of being included in Scripture. Revelation ends with a curse against anyone who tries to cut words out of the Bible. Almost exactly 1,000 years after that council, Laodicea was destroyed by earthquake and never rebuilt. (Sometimes God's prophesied judgment has a merciful waiting period of 1,000 years, a prophetic day, to allow the chance of repentance. Such was true with Adam and then with the Genesis reduction in human lifespan to 120 years, which was phased in over a 1,000 year period, concluding with Moses at the end of the 1,000 years). Every other one of the seven churches saw their city last until almost the end of their respective church age, and some faithful ones, like Ephesus, saw their city last until long after their time ended. Laodicea is the exception. That city only lasted about half way to the church age whose spiritual condition matches theirs. (Some people say that the church recently entered the age of Laodicea, while others believe it will arrive after the current wave of world missions concludes and that we are in the waning days of the church of Philadelphia, the missionary church.)

Supporting information:

Ephesus was destroyed by Goths in 263, partially destroyed by earthquake in 614, sacked by Muslims in 654, 700 and 716, and then entered a period of slow decline. It still existed during the time of the Crusades but was reduced to a small village. Thus it lasted long past its era of church history, which ended with the death of the last Apostle, John.

Smyrna had a Christian presence until the great fire in 1922, during a war between Greece and Turkey. It endured long past its era, which ended when the Roman persecutions ended in the time of Constantine.

Pergamum was promised and received the double-edged sword. It was captured, destroyed and rebuilt in the 7th, 8th, 11th, 12th and 13th centuries. By 1300 AD, it was an abandoned ruin.

Thyatira is last mentioned in historical records late in the tenth century, near the end of its era.

Sardis was lost to the Ghazi emirs in 1306 and destroyed by Tamerlane in 1402 AD, near the end of its era.

Philadelphia was also destroyed in 1922 during a war between Greeks and Turks, near the end of its era. Philadelphia represents the missionary age from the Reformation on.

Laodicea was destroyed and rebuilt several times, but another earthquake in 1354 AD spelt its end. This was 987 years after Laodicea rejected the Book of Revelation. It also falls 700 or so years before the start of the church age of Laodicea. It was the only city that did not endure to see the dawn of its church age.

Peculiar fact:

We do not know when Revelation was written, but Irenaeus wrote that is was written near the close of the reign of Domitian, who died in 96 AD. If Revelation was written in 94 AD, then if you add 1,260 years you get 1354 AD, the year that Laodicea was destroyed. The number 1,260 appears in several prophecies in Revelation. Curious?