Here is an extreme example to prove a point: I write a business plan and successfully raise money from investors. Then I hire people to do all the work, pay them salary, and give them much less stock than I take. I have the largest employee stake, but haven't done any of the 'real' work (unless you consider fund raising to be the real work).
This example is absurd, but it's useful to my argument: the founders get their stock by working for free, not necessarily for creating the critical foundation of the business. For some reason, this has been bothering me lately. It seems more reasonable to have a system where ownership is determined by contribution... otherwise there will always be the risk of the opposite: contribution being determined by ownership.