The candle/light bulb analogy is the wrong analogy. The correct one is the light socket/wall outlet analogy. When electricity was first run into homes, it was all about light. So houses would have screw in bulb sockets installed. As more useful electric devices became available, people screwed adapters into the light sockets to run their devices. What they really needed were wall outlets (the Edison plugs we have in the US today).<p>Wall outlets didn't kill the need for light sockets, they simply split off certain functionality that wasn't best served by those sockets, because those sockets were never designed for that purpose. Light bulbs killed the candle (except emergency, devotional, and mood lighting) and I don't thing todo, calendar, task management apps will kill email, but simply return it to it original, more limited purpose.