The world is not finite from any perspective, whether physical or economic:
- The world is not finite from a physical point of view, because it receives gigantic amounts of solar energy from the sun. Sure, it tends to radiate much of it back out, but a large chunk of that energy is converted into "wealth" in a biological form, via photosynthesis. That continually increased wealth is what has allowed us to progress from single-celled organisms to what we are today.
- The world is not closed from an economic point of view because work has a value (something your ilk seems to be arguing for, I believe) and new work is done every day. Every bit of productive work adds more value to the system, more wealth. Some people's work is more valuable because it creates more wealth. Those people are (and should be) rewarded accordingly, in a fair system.
You should read up on Microsoft's history. Bill Gates started off as a developer. He most definitely "did the work". Also, only someone who has never done any meaningful work in a business could possibly fail to understand that "management" work is not only very hard and complicated, it is also essential. Left to their own devices, most large groups of people devolve into chaos, producing no useful work whatsoever.
Finally...
There is a capital gain in people's work and their wages are far from covering it.
Of course. You're absolutely right. The reason for that is that the people receiving those wages did not take any risk. They receive a pay check at the end of the month, and they don't need to worry about whether or not the product will be successful, whether the company will get sued, whether key members of the company will suddenly leave and start a competitor, etc - they get their money anyway. The founders of a company take most of that risk, particularly at the beginning, and it is perfectly reasonable that they should get most of the reward.