Outside of purchased-and-being-shutdown, these are still frequently "we want to do things but we're scared of breaking things" situations, not "we don't want to do anything." Even if the things they want to do are just "we want to move off this 90s codebase before everyone who knows how it works is dead."

In that sort of high-fear, change-adverse environment "get rid of all the devs and let the AI do it" may not be the most compelling sales pitch to leadership. ("Use it to port the code faster so we can spend more time on the migration plan and manual testing" might have better luck.)