Following up on this thought, are health insurers already using such techniques to drive out unprofitable customers -- despite government regulations that they require coverage?

California stats suggest "yes", and for about 4 years now:

https://wpso.dmhc.ca.gov/dashboard/ComplaintsIMRs.aspx

Not only that, but a racial discrimination lawsuit. If someone can prove that one of the protected classes is getting worse service, it might make for a nice class-action. I’d love to see Zeta Global (among others) lose a few million for perpetrating this nonsense.