[throwaway29303]

  The job might not get done as well, or done in a different way than we'd do it, but it'll still get done.

If the job isn't done as well, then no one isn't as replaceable as you put it.

Excellence can't be replaced as easily. Maybe for certain kinds of jobs yes, but for all jobs? No. If that were the case then we'd be inundated with Einsteins, etc. And we aren't.

[marcus_holmes]

How many people have the opportunity to be Einstein?

How many people have the right brain, and the right interest, and write the right paper at the right time?

How many are starving in an underdeveloped country and no access to education, for that matter.

Einstein wasn't necessarily a unique genius standing at the pinnacle of an intellectual mountain. He was a beneficiary of survivor bias. We don't know how many other "Einsteins" there have been, or could have been, because we only tell success stories.

[throwaway29303]

  How many people have the opportunity to be Einstein?

Everyone who has access to (public) education, probably. And of those whomever has a relentless will for achievement. And/or is, by nature, curious about stuff. There's a reason why the lines between genius and mental illness get blurred sometimes. Remember John Nash, Jr.?

  How many people have the right brain, and the right interest, and write the right paper at the right time?

  How many are starving in an underdeveloped country and no access to education, for that matter.

I wouldn't know but I'd estimate millions.

  Einstein wasn't necessarily a unique genius standing at the pinnacle of an intellectual mountain.

Whether you like it or not, he was a genius, and unique in his own way (like everyone else is - even you), along with various other well-known peers of his time and lots of other people before them.

Now, obviously, they, as well as any "proper" scientist, are well aware that none of their work would mean anything if they didn't stand on the shoulders of giants. Science is a branching tree of giant people.

  He was a beneficiary of survivor bias. We don't know how many other "Einsteins" there have been, or could have been, because we only tell success stories.

Following your train of thought then no one's achievements - even those who you claim don't have the "right brain," "right interest," don't "write the right paper at the right time," are "starving in an underdeveloped country" and "without access to education" - would mean anything.

So, to get back to the subject: replaceability depends on the kind of job. It may be simpler to replace a fast food worker, but a Richard Feynman? an Albert Einstein? or <a name of a scientist whose name isn't publicly known but has made a difference in their field>? I doubt it. Those people made a difference in their respective fields and no one can take that from them. And I'd say the same if it were someone else from other countries, ethnicities, etc.