Shares are designed to provide owners with:
How would Ethereum based ownership make sure each owner, gets their share profits?
Is this even possible with Ethereum / smart contracts?
There are indeed many opportunities where Smart contracts can reduce the analog friction that is present with the current ownership of equity. The most obvious use case is of course the instant transfer of ownership that is paired with low costs and speed, due to cutting out the intermediaries and wet signatures. However, from there it's easy to go a step further. Once your companies shares are distributed it's a small step to do governance (shareholder / director voting) and funding via these channels.
However, there are still obstacles that limit a wide adoption of doing so. You always need a legal framework, thus a link between the digital and analog should be there, and that's a tough once to crack.
Otonomos is one of the companies that is doing exactly this, actually making it work with real world companies.
If all profits and losses are on the blockchain then everything can easily be managed with smart contracts. For example boardroom provides tools for governance of Daos and it is a simple matter to write a contract that disperses funds to different parties . However where it gets challenging is the interface with the 'real world' legal system. As far as I'm aware there are 4 approaches:
Note that none of this is intended to be legal advice or guidance. More generally you should be aware that most jurisdictions have strict rules on issuance and trading of shares and other securities so you should do your due diligence to ensure that you are fully compliant with all required laws and that members and developers personal liability is limited.