I think we simply underestimate the cost of software maintenance because we ignore software maintenance. Migration to a new language is nothing but an extreme

I think we simply underestimate the cost of software maintenance because we ignore software maintenance. Migration to a new language is nothing but an extreme form of maintenance. And it's not even that expensive. We're just used to scales of a dozen or so programmers at best. As a very conservative estimate, translation from assembly to, say, Java, should proceed at the pace of maybe 100 lines per day on average. So a team of 100 developers would need a year or so to translate a 20M lines application. Of course, there's also the effort to create tooling and the framework of the new application, but it's certainly doable.