Exactly. The value is in the mental model the development team has accrued through working on the code, not the code itself.[1][2] If you lose the code but retain the development team then the code can be rewritten. Lose the team but keep the code, as in this case, and you're left with a bunch of software that no one really understands how to maintain, much less improve on, without working at cross-purposes to the original design. For a new team to develop the same degree of experience and familiarity with the codebase as the original team is only marginally less work than reimplementing it from scratch. At that point the language it's written is the least of your issues.
No doubt. Just wanted to share my experience, and the potential risks of starting a large project (or acquiring one) in a language most 'coders' aren't familiar with :o