If a person learned to become exceptionally 'talented' in one area, then he/she's more likely to replicate that same level success in a completely new area, than someone who hasn't gained that level of skill anywhere. This is because skill acquisition itself is a skill. So once you've learned what it takes to master a certain skill (i.e. you learned how to learn effectively), you can then apply it with much more ease than someone who hasn't really learned how to learn as much. This causes a sort of 'snowball-effect' outcome, where ease of skill acquisition follows a logarithmic curve of sorts rather than a linear/exponential one like most people seem to view it.

The only limiting factor on skill acquisition is choice/taste. If a particular area doesn't interest you, then why bother expending energy learning to master it, right? Doesn't mean you're not capable of it, all it means is that you didn't have to strive for greatness in that area to make it work for you. And since Jobs met Woz pretty early on, there was really no reason for him to become a master engineer thereafter. Meanwhile, Woz probably just didn't care about business/marketing, so he chose to not master it.

There are other factors that influence skill acquisition (e.g. IQ), but they don't necessarily limit it. And in order for the 'fair' view of skill acquisition to hold, there would need to be some sort of non-trainable limiting mechanism for building skills. But as of now, I'm not familiar of anything that would cause that.

The only way the "Jack of all trades; master of none" mantra holds, is if the 'Jack' never deeply learnt/'mastered' any of the subjects he's familiar with. But of course, the label "Jack of all trades" doesn't actually specify whether-or-not that's actually the case. Same for "well-rounded"; implying it indicates anything other than breadth of knowledge is inaccurate.

Greeks celebrated such great thinkers. Leonardo da Vinci, Michelangelo, Galileo Galilei, Nicolaus Copernicus, Francis Bacon and Michael Servetus were all amazing polymaths. - They had expertise in Math, Engineering, Philosophy, Art, Finance. (Perhaps not marketing because such a thing didn't exist back then.)

There have been such multi disciplinary experts in the world and I'm sure there continue to be. But they are rare and often found pursuing interest in one of the areas.

If you can understand tech there is no reason you cannot understand sales and vice versa. - In fact being blind to an alternative point of view isn't even a feature of a man of class. And if you can understand it, why can't you think the same way.

There would be no Apple.