This isn't thinking far enough outside the tiny box of this specific economic order at this specific point in history. For example, we could have co-ops instead of corps.
The vast majority of businesses fail, and many businesses go through cycles where they make less money than they spend. How can the average person take on the risk of not getting paid for years? One year of non-profitability would be a death sentence for a co-op if people can't get paid and flee.
A corporation allows the average person to get paid while someone else takes on a risk with their money.
