1) I doubt The Economist is suggesting that technical complexity is the reason they think that something like Wikipedia won't happen again.

2) You still have LAMP, even if the A is now often Nginx and the M Postgres. That stack is at least as easy as back in the day (signed someone who in my teens loved PHP so much that I made CLI utilities and IRC bots with it, auch). But that's besides the point, because several programming languages and web frameworks now come with their own built-in web-server for development, so you don't even need a stack to get started! This part is easier today.