People soon found out that it was not very good at complex web apps, though.
These days, there's almost no demand for very simple web apps, partially because common use cases are covered by SaaS providers, and those with a need and the money for custom web apps have seen all the fancy stuff that's possible and want it.
So it's no surprise that today's languages and frameworks are more concerned with making complex web apps manageable, and don't optimize much (or at all) for the "very simple" case.