I think that Microsoft would make more money if those "500 million!" XP users woke up one day, realized their 10-year-old XP tower no turns on, and were forced into buying a newer PC.
Problem is, this is not a great time for that. Should have waited for Windows 9 to be released. ):
You can have an async implementation and synchronous code. http://meteor.com does that part quite nicely. The compiler or runtime should be handling this kind of cruft for us in most cases. Just because using Brainfuck might result in theoretically faster code than Ruby doesn't mean we should be writing our server in Brainfuck.