You brought up some very good points. You brought up the fact that 80% of all small businesses fail. Is the underlining reason that these people also don’t pour their blood, sweat, and tears into business? No. Simply he is out invested by more efficient businesses who do can do things at a lower cost. Unfortunately those businesses turn out to be monopolies.
During periods of slump, the bigger capitalists, with economies of scale, are better able to survive. Capitalism has an inherent tendency to concentrate into monopoly. They also try to get out of these crises by selling goods on foreign markets. However, all the other capitalists are trying to do the same and the world is only so big. Also in the very act of exporting to foreign markets the capitalists develop the productive forces in these countries (eg. Indonesia, China) which then start producing a surplus for export - exacerbating the problem. The only solution at this point is to take these foreign markets by force.
Of course there still exists a huge “demand” for workers - houses for the homeless, or food for the hungry, or medicine for the sick - but for a capitalist, demand only means anything if it is backed up with hard cash. Capitalism gets itself in this mess because it produces for profit and not for need.
Now let’s use money, the basis of capitalism. Let’s say you have a $10,000 bill (they exist). You could use it to go and buy a 48-inch HDTV, a small motorcycle, and 200 pounds of candy. That bill cost the US government less to print than a sheet of newspaper. So why does money work? You can’t take a newspaper and buy a motorcycle. But everyone in the world is in on a secret. Everyone is going along with a deal: they’ll pretend your scrap of paper is worth a motorcycle as long as you will. You can’t take this bill to a government bank and exchange it for gold. Money is nothing but a promise everyone’s made with everyone else.