Each one was supplanted by the next gen for "coolness".

The next thing after TikTok is going to be whatever gen A/B/C decide are the "cool" platforms. It could be a new 4th or they might recycle an old platform, the way that Adidas and Reekbok and Fila came back for sneakers for a bit.

For corporate social networking, the inertia of "cool" doesn't necessarily have an uncool factor that needs to be overcome in a similar way.

Will be interesting to see how the space plays out though.