Why the churches in Revelation were in danger of dying

I was sat wondering: what did the churches in Revelation get wrong? Why were they on the verge of dying? So much of the talk about dying churches today (and the remedy for it) focusses on evangelism. Here's what I found by asking a couple of basic questions:

What were they commended for?

• I know your deeds, your hard work and your perseverance. I know that you cannot tolerate wicked people, that you have tested those who claim to be apostles but are not, and have found them false. You have persevered and have endured hardships for my name, and have not grown weary. (2:2,3)
• You have this in your favour: You hate the practices of the Nicolaitans, which I also hate. (2:6)
• I know your afflictions and your poverty—yet you are rich! (2:9)
• I know where you live—where Satan has his throne. Yet you remain true to my name. You did not renounce your faith in me, not even in the days of Antipas, my faithful witness, who was put to death in your city—where Satan lives. (2:13)
• I know your deeds, your love and faith, your service and perseverance, and that you are now doing more than you did at first. (2:19)
• You have a few people in Sardis who have not soiled their clothes. (3:4)
• I know your deeds. See, I have placed before you an open door that no one can shut. I know that you have little strength, yet you have kept my word and have not denied my name. (3:8)
• You have kept my command to endure patiently (3:10)

What were they taken to task over?

• You have forsaken the love you had at first. (2:4)
• There are some among you who hold to the teaching of Balaam, who taught Balak to entice the Israelites to sin so that they ate food sacrificed to idols and committed sexual immorality. Likewise, you also have those who hold to the teaching of the Nicolaitans. (2:14,15)
• You tolerate that woman Jezebel, who calls herself a prophet. By her teaching she misleads my servants into sexual immorality and the eating of food sacrificed to idols. (2:20)
• I know your deeds; you have a reputation of being alive, but you are dead. Wake up! Strengthen what remains and is about to die, for I have found your deeds unfinished in the sight of my God. (3:1,2)
• I know your deeds, that you are neither cold nor hot. I wish you were either one or the other! So, because you are lukewarm—neither hot nor cold—I am about to spit you out of my mouth. You say, ‘I am rich; I have acquired wealth and do not need a thing.’ But you do not realize that you are wretched, pitiful, poor, blind and naked. (3:15,16)

Were any of them upbraided for being insufficiently evangelistic? No, none of them. A number were on the verge of dying, of having their candlestick removed - not because they didn't speak about Jesus but because of the quality of their lives and their compromised faithfulness.

Does this have anything to say to us?