Maybe not the most expensive but it is certainly potentially one of the most costly. Look at Facebook with PHP and Dropbox with Python. It's the sort of thing you can overcome despite the odds (as both those companies did), but can also tip an on-the-edge company into failure.

Same thing with the fundamental architecture of programs, and especially the data model & database solution.

Still I don't entirely agree with the article. He makes it sound like there isn't any difference between programming languages and any preference is purely about developer identity. But that identity doesn't come from nowhere. Rust is popular because a load of C++ developers finally found something technically better. Not because they all woke up one morning and decided to be "a Rust developer".

Where the story falls apart is that Perl is arguably even worse than PHP. One deluded Perl programmer does not prove a principle.

On Rust vs Go, he's absolutely right that Go is has a slightly better "build & deploy" story (though not by a much). But reading between the lines I think he's misrepresenting that - it sounds like a) that was just one point for choosing Rust, and b) that was a point when comparing to typical alternatives, e.g. C++ or Java. It's not untrue that Rust is easy to build & deploy simply because Go is slightly easier.

> Look at Facebook with PHP and Dropbox with Python.

What about them?