[sjy]

The problem with your first two examples is that the 'investment' locked up in the smart contract can't be spent, which means the investors are not bearing any risk, and therefore cannot enjoy a return. If the money could be spent on capital and operating expenses, then the smart contract wouldn't be able to refund it if the conditions of the investment failed.

It is possible to create a smart contract, like the DAO, which implements the rules of a joint stock company. But stockholders are not concerned about the risk that these rules will be broken. The risk is that the company fails and there is nothing to distribute according to the rules. Replacing the general meeting of stockholders with a smart contract doesn't change the economics of collective investment – it just adds the risk of losing everything to a bug in the contract.