You're definitely right that data scientists are eating into the demand for actuaries. That's why both societies have added data science esque syllabus material. They are working hard to keep actuaries prepared for future demands of companies managing risk.
I think the thing your logic is missing is that if the SOA or CAS waters down the credentials and make them easy to get, the usefulness of employing a credentialed actuary also goes down and that is problematic for the societies.
On the other hand, I think SOA/CAS have both expressed desire to become more global which serves a growth goal. That is, each society is definitely interested in growth, and a growth-focused mindset is susceptible to making decisions like "If the exams are easier, we'll have more dues paying members!"
But that is a delicate balance with maintaining the "prestige" of the credentials that employers are looking for.