You have to learn to cook because restaurants serve poisonous crap. You have to learn nutrition because supermarkets mostly sell poisonous crap which you need to avoid. You have to learn medicine because doctors are corrupt morons with no understanding. You have to learn all critical skills because humanity has turned to shit and there is no one that you can trust to do things right.
If you specialize in something and become very good at it, you will only be hated for this because modern scum hate all good things. Your insights will be ridiculed and no one will want to work with you. Modern scum only want to work with mainstream moronic scum.
So specialization makes no sense. In the modern world of moronic modern scum, decent people need to be generalists.