And now the cost of hosting a hundred webapps is just a rounding error in contrast to the cost of developing one.That's a weird way to look at it, unless you're in the webapp hosting business? For everyone else there is usually only one webapp that they care about.
I can take the same program and handle 20,000+ concurrent users on two servers
Sorry to break it, but that's not how it works. Unless you have one of those rare webapps that never need to touch a database.