Industry is a type of trade or manufacture, it can also refer to trade and manufacture collectively. Those things will often happen in an industrial environment. Industry may also mean great activity or diligence. Those who demonstrate this are industrious.

Publishing is an industry. We don’t always like to think of it that way, but it is. In common with most other industries money is the main driving force. It’s often not the only one, but it’s very important. If (for example) a magazine doesn’t sell enough copies to buy more paper, it can’t print the next issue.

If my books don’t sell, I won’t be able to afford the cake needed to fuel me as I write the next one. You wouldn’t want me to go without cake, would you?