A startup with talent theoretically follows that pattern. If you're not a startup, you don't need to go fast in the beginning. If you don't have talent in both your dev team and your management, the codebase will get worse over time. Every company can differ on those two variables, and their codebases will reflect that. Probably most companies are large and talent-starved, so they go slow, start out with good code, then get bad over time.