Why? If a worker loses his job, he also has to sell his labor-power on the market.
But if the investor diversified well his investments, he's likely to have lower risk than an average worker.
Ownership requires management and the steps which were required to achieve that ownership. Somebody maybe had to work hard to own, while others inherited.
Yes an investor has lower risk than a worker. A worker depends on continually selling his labor-power to survive. He can't do that if he gets sick or injured, if he gets laid off, if his area of expertise gets automated out of existence, etc. When an investor makes an investment all he risks is maybe eventually having to become a worker (only a real potential for small investors and small business owners).
But if the investor diversified well his investments, he's likely to have lower risk than an average worker.
Ownership requires management and the steps which were required to achieve that ownership. Somebody maybe had to work hard to own, while others inherited.