I think he meant don't invest in others businesses, start your own. Depends on whether you're good with money and bookkeeping, etc I suppose.
Yeah indeed starting your own business isn't a easy thing which you can do in one two three, you need knowledge for it and a capital aswell.
I wouldn't start my own business, way too much working hours and risk for me to be worth it but ofcourse you could live very wealthy if you succeed.