This to me is the sticking point. The biggest benefit to society for patents is: you get the formula (but can only use it once the patent expires). I would imagine that no one short of lawyers has ever bothered to read expired software patents. They are literal drivel and until they are useful to have disclosed, they should probably not be patentable, in my opinion.

Exactly — but for all practical measures, it does not differ if they release it in the patent, or only when the patent runs out.

Currently, they don't release it at all.

Additional regulation I'd like to see: Any neural networks trained based on data of users have to be completely public domain. If Google wishes to train recaptcha, they should either pay for people to train it, or give back to the public the value that the public created.

It does matter, because if the publish it in the patent I can start planning to build something with years before the patent expires, or time improvements I make on it for that expiration.