Sure, but the point is that the JVM makes you pay that memory cost up-front, so it looks a lot more resource-heavy than it really is, whereas the scaling cost o

Sure, but the point is that the JVM makes you pay that memory cost up-front, so it looks a lot more resource-heavy than it really is, whereas the scaling cost of things like PHP and Ruby is back-loaded. People worry about scaling too much in general, IMO, but you'll actually get more mileage out of your hardware with something Clojure or Scala than you will with Python/PHP/Ruby/Perl.