Large code bases are rarely rewritten from scratch. They evolve over many years, and over time, old code gets replaced with new code, piece by piece. If a langu

Large code bases are rarely rewritten from scratch. They evolve over many years, and over time, old code gets replaced with new code, piece by piece. If a language evolves over a similarly long time span (10 years or more), and new features are adopted gradually, I don't see why a backward-incompatible change would require anything more than the usual amount of change when the last of the old code is retired. Call it inertia if you want, but this looks to me to be a good thing if you have a large code base to maintain.