What makes you think that a person 30 years into a career hasn’t been learning? The peril of specializing is that some day your field might be rendered obsolet

What makes you think that a person 30 years into a career hasn’t been learning? The peril of specializing is that some day your field might be rendered obsolete. On the flip side, if you avoid depth of knowledge, you will also be replaceable and never progress in your career.