That's a massive hard-no for me. I generally only get faster the longer I get to work with a Ruby codebase, as I get to make it more and more into a DSL for the business situation. I never saw that happen with compiled languages; my speed tended to remain constant after the initial boot.

I know what you're talking about tho - it's the sharp knives + large team problem. The language doesn't maintain a standard of code for you, you (and your team) have to do that yourselves, and if you don't, things can very much get bad. If you're programming in a loosely typed language such that you're effectively having an explosion of types, you're suffering one of the more common downsides to typed languages and you're not using the common upsides to loose typing.

That said - when I'm working, the main difference I've seen with Ruby (and, to a lesser extent Python and JS) vs compiled is the iteration loop, particularly due to having a REPL console. Static languages have definitely made some gains there (looking at you, Scala REPL). Being able to drop into both any debug point in the program, as well as a console loaded with your code, makes certain explorative processes substantially faster.