It seems impossible to me but I would love to be surprised.
It sounds perfect. But how would we achieve it? Rewrite laws that prohibits private property and free enterprise?
One idea could be to collectively pool money to give as rewards to anyone who improves society in a way that people think is worth rewarding. To prevent corruption this process should be transparent and democratic (preferably direct democracy).
Because it takes lots of work, risk, and sacrifice. If rewards are small (which, obviously, they would be in your scenario where people pool their money together to reward someone), then why take on such difficult task? I know I wouldn't be trying to do any business in your system. Many wouldn't.
The risk part is a problem, I agree. If the risk is larger than the potential reward, it isn't worth it. The risk should somehow be collectively handled as well.
I'd frame the problem as follows:
"Capitalism is a powerful tool, but fails as the sole guiding principles of a society's values. Christianity, a former enabler of pro-social norms on a massive scale, is dead.
Wat do."
"SCIENCE says we're all living in a simulation, and probability suggests it was created by a COMPUTER."