"Your margin is my opportunity" - Jeff Bezos
A simple version of this could be done cheaply, and not cost much. API to push events, website to host reports, pay-for-use add-ons for alerts, etc.
Here are some of the reasons why this niche isn't a good fit for a low margin business:
These products are complex and require extensive customization to be useful. It's common to require consulting when installing or upgrading them.
Third-party integrations are common; the product that I support integrates with at least 3 third-party services.
The service is valuable to these organizations and they are willing to pay fairly high fees for using it. Why leave money on the table?
Support costs are high due to the complexity of the customer's environment.
But go ahead and find a random group of 3 ex-googlers with no domain experience to raise ~$2MM and chase it anyways. Then when you burn through the money you can go back to your FANNG job with a nice raise.
This kind of system are already used to both optimize business processes and conformance check then by organizations like banks and hospitals.
Through tools are currently focused mainly on the use case for process optimization and regulation conformance checking less so for irregularity detection but tools like that exists to. I think to remember SAP has some form of self learning/calibrating irregularity detection "service"/tool.
So it's less about creating it then about spending Mony on it and from scratch up analysing your internal thread model.
It's quite expensive, some of this software is sold for higher 5 digit numbers even for "small" use-cases.