"Rich Dad" does seriously advocate real estate, not to the exclusion of those other options but certainly above them. Real estate stands out mostly because of the leverage that a mortgage can provide: you can control the income and appreciation of a $250,000 asset with only $50k of actual capital. You can't get 5-to-1 leverage on stocks or other such passive investments.
That said, real estate is certainly no magic bullet. You certainly take on risk, of depreciation and vacancy time and deadbeat tenants. And it's hard work to keep a property maintained or expensive to hire someone to do it. It's not for everyone. These are the points that "Rich Dad" doesn't make and must be included for a balanced perspective.
5 to 1 margin on stocks is not hard to achieve, it's just more risky than 5 to 1 on a mortgage because your position is marked to market where as mortgages are not marked to market, but are much more illiquid.
That said, real estate is certainly no magic bullet. You certainly take on risk, of depreciation and vacancy time and deadbeat tenants. And it's hard work to keep a property maintained or expensive to hire someone to do it. It's not for everyone. These are the points that "Rich Dad" doesn't make and must be included for a balanced perspective.