Start throwing people in jail and fining billions of $ and you will very quickly see the number of "incidents" drop. You will never learn if it's because they truly are happening less often.
Pilots do not (or no longer) self-report mental illness at the same frequency because it effectively destroys their lives and career. One paper of many describing this phenomenon: https://pmc.ncbi.nlm.nih.gov/articles/PMC11302551/
An article, one of many: https://www.reuters.com/investigations/if-you-arent-lying-yo...
If you have any pilot friends in commercial aviation, you can just talk to them as well.
So getting pilots to self report has been very unsuccessful because of how badly it ends for them.
A couple of days ago the senate had to pass a bill to make mental health medication access easier for pilots. We will see if it helps, but it doesn't solve the root cause (punitive measures) so I doubt it'll move the needle.
I do agree with you that a proper regulatory framework with clearly defined obligations is better than one off overly-punitive fines and arrests.