Yes, seriously. In what sense are JVMs "specialized for long-running applications"? If you mean they start slowly, that's hardly the case even if you start from scratch:

   > time java HelloWorld
   Hello, World!
   java HelloWorld  0.28s user 0.06s system 135% cpu 0.248 total

In any case, the JVM is just an example (although I still argue it can serve this purpose well). My main point is that the "correct" model for the web is a bytecode-running VM inside every browser that lets you do everything javascript does through APIs.