Formal verification does not gurantee business logic works as everybody expected, nor its future proof, however, it does provide a workable path towards:

Things can only happen if only you allow it to happen.

It other words, your software may come to a stage where it's no longer applicable, but it never crashes.

Formal verification had little adoption only because it costs 23x of your original code with "PhD-level training"

The reason it doesn't work is businesses change faster than you can model every detail AND keep it all up to date. Unless you have something tying your model directly to every business decision and transaction that happens, your model will never be accurate. And if we're talking about formal verification, that makes it useless.