Credit/VC? Or you start a co-op dairy / farm / repair shop and work for centuries towards arriving at where JD is today (by which time big corps would have moved a few centuries ahead).
VC works plenty well. It's a business deal. 100% of a $0 business is $0, so in exchange for enough money to jump start the business that you don't have the funding for, you give up some equity so that in the eventuality that you're successful supplanting John Deere, your investors get paid out. That's how the system works.
No, it doesn't work. If you let VC invest then you cease to be a worker co-op, you become a regular business.
Worker co-ops have only one class of member: worker-owners. People who do both the day-to-day work and are part owners of the business. Unless the VC people are willing to show up and start punching the clock like everybody else, they are a different class: owners who don't work. Worker co-ops disallow that class of membership by definition.
So select for investors who can stomach a specified return, so the company doesn't have to IPO, but can instead buy them out. After the coop is able to generate revenue to and is able to buy out the initial investor's initial investment, and give them a return between 10 and 100x, it reverts to being a traditional coop.
So the solution is to invent a time machine, and go back in time to the days before factories (or internal combustion engines) were invented and stuff was manufactured (with "man" coming from Latin for "hand") by hand in cottages, and start your co-op then.
some of the most successful Danish agricultural companies started out as / are cooperatives.