[katzgrau]

Joel classic, and it always reminds me of times I've seen this happen again and again years after it was written. I don't think I've ever seen a full rewrite bring all of its heralded benefits. I'm sure there are some people who have. There always end up being things the old system did better, and sometimes you wind up with the old and new systems running in parallel because end users need to switch back and forth until v2 is finally mature (it seemingly never finally matures).

That said, I'm in favor of a rewrite when the use cases for the platform have diverged so significantly that you essentially have to bend it in half to make it do the thing that users want it to today. That is, as some point the core use cases have changed, perhaps via a pivot, and you need to build a product that is essentially new as compared to the old.

Regardless, the cases where I've seen a rewrite take place are when the engineers are young, talented, and enthusiastic about new tech and the engineering manager doesn't want to piss them off so they let the devs play (most of them will be off to other jobs in 2-3 years leaving behind a system that is debatable as ugly and busted as the old).