You've just touched on why it's so hard to get a job in tech. As a culture, we've taken an attitude that credentials don't matter, and no matter what our past achievements are, we've got to prove ourselves over and over again. Maybe credentials should matter.
This makes sense for hiring a human. It doesn’t make sense for evaluating what they say in a general context. Credentials are fairly useless next to consensus for evaluating a given statement.
Credenials have use; just not in conversation.
This is a level of cognitive dissonance I’m not prepared to commit to arguing against. I’m not capable of issuing the bar to every lawyer I require the services of, nor the board to every presumed doctor, nor a thesis defense to every academic.
Credentials aren’t perfect, but they are superior to the time required for everyone to judge everything on their own. For example, almost all scientists agree that climate change is human caused. Do I spend my time digging through climate data, verifying this? No. I rely on the expertise of experts.