> Developer & time-cost of a rewrite is a big unknown... An optimist might say this cost has vanished.

I wouldn't say it vanished. I'd say it moved from unknown to known. It's highly likely that for code the size of Bun the price is around 200k dollars of tokens + a month of programmers time to monitor it.

> Shipping a rewritten product is -by itself- an unknown risk. That still holds. You can do all the testing you want, but your test suite != your clients environment(s? multiply by number of users or target platforms).

Fair point.

That said, it seems the number of relevant platforms is shrinking. Both on the hardware side - x86_64 AMD, x86_64 Intel, and aarch64. On the OS side, you have Linux, Mac and the dying Windows.

Still, it seems with enough tests and original source code, you can limit this risk to a few edge cases.

> All in all Joel's article held up pretty well

Aside from the fact that it mostly applies to commercial endeavors[1], it still missed the mark on old code decaying over time.

Turns out being exposed to the Internet has a chance to turn even old code sour.

[1] If you don't care about your users, or you care more about pleasing/attracting new developers, then points made in his article don't make rewriting it that bad.