To answer your questions:
But why should I spend my time mining minerals for lower isk when I could rat and use the money I make there to buy the minerals I need to manufacture stuff as passive income?
From a purely profit motive point of view, you shouldn’t. If you can make more isk from carrier ratting than from mining, you should carrier rat. If carrier ratting becomes sub-optimal for some reason, do what makes more isk.
So I ask the community why should I not just sell my mining characters and/or skill injector off their skills and just using a carrier on 1 account?
Maybe you should. If you don’t enjoy the process of mining, don’t feel it will ever be worth doing, or feel you will never mine again, it may be worth while to sell the SP or characters.
Here are some reasons to keep them though:
- If the market shifts and mining becomes more profitable than carrier ratting, you can jump into mining quickly and easily. This can happen for various reasons, including if enough miners give up mining.
- You’ll have an option for another activity if you get sick of carrier ratting
- You can contribute to corporation/alliance mining operations