Based on Grok identifying the company correctly, that would amount to ~3% of annual revenue and 30% of profits which seems insane to me for the cost of a single project.

Anyway, even if that were true, rewrites are becoming drastically cheaper, simpler, and more correct with AI. The Bun rewrite is the largest experiment and seems to be 5-10x cheaper and completed ~100x faster and these costs are likely to come down further. So your claimed $1B rewrite today costs $100M and carries less risk. In 5 years it'll probably cost at most $10M and be finished drastically more quickly. And the vast majority of software doesn't cost $1B to translate.

Btw grok found out in less than ten seconds what place you refer to and likely what software within that company.

Things that wouldn't be worth your time before are trivial these days with LLMs.