Comment by xp84

> RoR was so brittle and slow that they couldn’t hire enough to keep it going.

This is such a "poor carpenter blaming his tools" take.

RoR isn't holding you back from writing performant, high-quality code. However, letting inexperienced developers run wild without supervision does end up with a codebase committing most of the deadly sins of software: (1) proliferation of competing patterns (2) proliferation of competing third-party libraries, leading to more #1, (3) inadequate test suite, and (4) an app that serves up so many 500 errors that you can't tell which are new and/or which indicate a problem. #4 is definitely more common in untyped languages, since that whole class of bugs can't be caught at compile time.

By the time a lot of these "startups" get to the mature state they have like a 7-year-old codebase that is beyond help. But you can use Ruby and Rails responsibly. I've seen it done. Usually all that's needed is to apply yourself to understanding how to cache, and then, identifying the key expensive high-traffic endpoints and converting them from ActiveRecord N+1 messes into single-query eager-loaded beasts, sometimes skipping ActiveRecord's object instantiation. Sounds scary, but it's inevitable for a popular application on any language/framework that you'll need to go beyond the tutorial-grade code for key transactions. This kind of thing is what Staff Engineers are for.