While the dead stones of Herod's Temple were separated from each other and "not one . . . left here upon another," the living stones of God's spiritual house are being built up (I Peter 2:4-5)! Jesus Christ, the Chief Cornerstone, used the same word in telling Peter that "on this rock [Himself] I will build My church, and the gates of Hades shall not prevail against it" (Matthew 16:18; emphasis ours throughout). Christ's church—that spiritual organism—is being built up, not torn down!
Paul uses a similar metaphor in his first epistle to the church in Corinth:
For we [ministers] are God's fellow workers; you are God's field, you are God's building. According to the grace of God which was given to me, as a wise master builder I have laid the foundation, and another builds on it. But let each one take heed how he builds on it. For no other foundation can anyone lay than that which is laid, which is Jesus Christ. (I Corinthians 3:9-11)
He employs similar language when writing to the Ephesians:
Now, therefore, you are no longer strangers and foreigners, but fellow citizens with the saints and members of the household of God, having been built on the foundation of the apostles and prophets, Jesus Christ Himself being the chief cornerstone, in whom the whole building, being fitted together, grows into a holy temple in the Lord, in whom you also are being built together for a dwelling place of God in the Spirit. (Ephesians 2:19-22)
Notice the positive progress in these passages and the sense that the building of God's spiritual Temple continues unabated—and as Jesus promised, the gates of the grave will not prevail against it. It will always exist in some form. For Matthew 24:2 to refer to spiritual stones, it would mean that not one Christian is left on Jesus Christ—the Cornerstone! Yet who are Christians, if not living stones on top of the foundation of Jesus Christ? As long as the church exists (Matthew 16:18), there will also be at least one living stone upon another.
This does not mean that the church of God will always exist in the same form or that it will be without turmoil, division, and even scattering. These are natural byproducts of carnality, so it follows that unless every member of the Body rids himself of all vestiges of carnality simultaneously, there will always be those forces that tend to divide. Intriguingly, God uses those same elements to work out His perfecting of us. Even when the church is in a relatively stable form, it is still subject to persecution from without, as Jesus warns in Matthew 24:9 (see also John 16:33).
Switching metaphors, on top of this the Good Shepherd moves His sheep around in ways that we sometimes cannot understand until after the fact. Thus, the life of a "living stone" will never be static for very long.