This debt isn't worth anywhere near 50% face value. More like 5%. This isn't a company that missed a payment or two. This was obviously planned in advance. There is simply no way there is any money left in any company account, which means virtually no chance anyone will ever collect anything.
Quite possible that you are right, but stealing all of that money and getting away with it? I find it difficult to sit by and just let it happen and then forget about it like it never did.