I suppose it all depends on what an individual wants to optimize for. If one wants to optimize their life for happiness, then changing careers is an option even

I suppose it all depends on what an individual wants to optimize for. If one wants to optimize their life for happiness, then changing careers is an option even if it means less money. But if one wants to optimize for money/title etc (which is what most people do, right or wrong) then it is better to stick to one career and get as good at it as possible.