There's three ways to raise money. You can finance it (debt) or you can sell ownership (equity), or the last one, people can randomly throw money at you and expect nothing in return. The last method of raising funds are donations, those aren't an asset that can produce dividends, or earn interest, that's the opposite of an investment, it's an expense. A charitable one generally to get more favorable tax incentives.

Of course you can have equity in a non profit. That doesn't mean your entitled to profits that don't exist, it means you have a stake in the organization. And the # of outstanding stocks versus the # of stocks held by the general public is a tiny fraction of what the Packers are worth, but again those silly pieces of paper are not proof of equity or ownership, it's literally memorabilia fans traded cash for a piece of paper that says they own something even though they have no power of ownership, the annual shareholder meeting is for show, so to call it an investment like a traditional stock would be isn't fair, it's really not the same thing.

What you are describing is development office, going out to ask for donations for a cause. That's not the same as running a venture that's going to make profit for shareholders.