More accurately: If me and me friends lemonade stands makes $1 million on it's own and your lemonade stands makes $1 on it's own. We bring them together and make $1.1 million because we had an amazing product and you are an amazing sales guy (yay!).

How do we divide the extra $100k. Are you pretending that you should get $50k (50 thousands times what you were doing alone) and we should get $50k (1.005 times what we were doing without you) as well ? That does not seem very fair to me at all.

Some of that extra $100k should probably go to the company, but sales is maybe not the best example because salespeople are quite often paid on a base+commission basis and would easily get a fixed percentage of all of their sales for the year. It seems high for sr engineers to make $500k/yr but it should be noted that senior sales people can also make $500k/yr if they're doing well!

Not necessarily. If you add a 3rd person, C, that also can make $1 alone, but $5 with person A, then person A's worth is somewhere between $2 and $3 if my intuition is right (i.e. B would need to agree to uneven split to convince A to work with them). This falls under computational social choice field (coalition formation), and is not a straightforward thing to compute.

The analogy doesn't apply. In this case, there are thousands of other employees and you together making $4. Not just two people.