Didn't you use expert systems 10 years ago for those? Rules running of SQL queries, which you crafted yourself or through the help of a domain expert? I think

Didn't you use expert systems 10 years ago for those? Rules running of SQL queries, which you crafted yourself or through the help of a domain expert? I think its fare to claim that companies who skipped that process might want to consider it first, as a cheaper way to start with predictive analytics. But, I'm not sure, I am actually intrigued, what was the techniques used before ML in that field otherwise?