Why factory/manufacture business tend to make a lot of profits?

Everytime I see people around me here in my country (Indonesia), it seems that the wealthy ones are usually the one whom:
1. do business (instead of just “normal jobs”), and also
2. do factory or manufacture kind of business, such as furniture, oil company, coal mining, etc etc.

My question is simple one, well, make it two:

1. Why or how come these type of business are always making very large amount of money & profits, and thus make the Owners wealthy, ie: i’m talking about buying three nice cars, a big house, can send their children to study overseas, etc

2. Is this really the only and ONLY way to get the most money (other than playing/investing in stock/financial market) nowadays??
what if let’s say I want to enter a music business (I’m an indie musician/songwriter), won’t I ever able to make as much money and wealth/profits as those type of businesses I’ve mentioned earlier?

Please give some general explanations of why this is (or SEEMS to be) often the case.
thanks.