The actual death penalty is not a good idea for several reasons, including possibility of error (even if that possibility is small).

(In the case of a corporation, also many people might be involved, some of whom might not know what it is, therefore increasing the possibility of error.)

However, terminating the corporation might help (combined with fines if they had earned any profit from it so far), if there is not an effective and practical lesser punishment which would prevent this harm.

However, your other ideas seem to be valid points; one thing that you mention is, government monopoly can (and does) lead to corruption (although not only this specific kind).