You're saying that businesses generate value. No disagreement from me there.
But then you're saying that stocks are the only way to share the value that businesses create. That's where you lose me. Selling shares is not the only way for a company to raise funds to operate. Companies can also sell bonds or take out loans (i.e. cash). Your argument that stocks are inherently more valuable would only make sense if stocks were the only way to invest in a company.
Companies get funding from two sources, equity and debt. The sum of those are equal to assets in the balance sheet. Both represent different forms of ownership of the company. Equity holders decide how the company is managed, debt holders have priority in income distribution and in liquidation.
Someone already owns a company before company sells (issues / dilutes) shares. That ownership is just shares. No shares need to ever be sold for them to exist. Founders create shares out of nothing when they create a business.
If companies don't sell shares, then there's no stock market. If there's no stock market, then there's no rate of return for stocks. If there's no rate of return for stocks, then stocks aren't an inherently superior investment to bonds, cash, or goods.
If someone founds a company that's 100% owned by that one person, then you (as an outside investor) aren't partaking in any of the value that that business creates. Let's say you want part of the ownership of that company. Companies don't just give out shares of ownership because they feel like it. Companies give out shares because they need liquidity. They can exchange fractional ownership for liquidity directly (e.g. selling shares) or indirectly (e.g. giving employees stock options instead of salary). However, shares are not the only way for companies to gain liquidity.
Ownership that is not traded has no value to investors. Ownership that is traded is traded for a reason, and must be compared to alternatives. Those alternatives are not inherently less valuable than shares.
The highway down the street from me was funded using Bonds. I even own a few Hospital bonds, which were used to construct hospitals.