That's what one should do, but I generally see the incentives setup all wrong. The most common scenario is that the fresh young smart ** hoodwinks the boss int

That's what one should do, but I generally see the incentives setup all wrong. The most common scenario is that the fresh young smart ** hoodwinks the boss into giving them 1-2 years and 2 subordinates to help them do the rewrite in isolation. They come off all support rotas and have no responsibility for BAU operation of the old codebase. The old codebase is left with usually a same or larger team maintaining and still adding new features. The other way I've seen this done is that senior management really wants the rewrite, shops around for a candidate internal or internal who promises to do it.. and then basically same setup as above. Setting up an explicit "good" and "bad" team creates awful vibes, the "good" team never delivers and starts exiting as accountability starts to creep in. Meanwhile the "bad" team hemorrhages staff continuously from the burn out of maintaining the old thing with less people while also being told your job has an expiration date.