> This isn’t true, a car mechanic never evolves into an engineer, a nurse never evolve into a doctor.

“Doesn’t generally happen” =/= “is literally impossible”. The word “never” should be used with care.

> A car mechanic can learn to do some tasks you normally need an engineer for and same with nurses

This statement can only make sense if you regard titles as something that’s imbued upon you, and until it is, you are incapable of performing the acts that someone who has earned that tile can perform. I’ll just say I fundamentally disagree with this notion on pretty much every conceivable level, and if that’s the belief system you subscribe to, that would also makes arguing about this any further pointless. But I might just be getting you wrong.