> The bar does not exist to serve lawyers, it exists to regulate them.

Those are far from being in opposition. A cynic might say the bar exists to serve lawyers as a class by doing the bare minimum to appear to be regulating them.

From the perspective of a lay person, it doesn't to be effective in doing so.

eg. Places like Prenda Law being able to operate openly for years before being shut down, etc.

It exists to avoid the courts stepping in to regulate them. If it weren't for the bar association keeping the worst out of view there would be a lot more lawyers reprimanded by judges instead. This is probably efficient, but not a sign that the bar association serves individual lawyers. It serves them collectively by keeping the dirty laundry within the organization rather than to submit to outside regulation.