Are start uppers copying how Carmack started to do software? I don't understand why there is so much need for raising money when all you need is a roof and a co

Are start uppers copying how Carmack started to do software? I don't understand why there is so much need for raising money when all you need is a roof and a computer to do this job. I know that not everyone is talented like carmack, but sometimes I wonder if money is not spoiling and troubling the IT sector. So in fact a startup might think it failed because it doesn't have enough money or because investors don't want to raise funds, but the reality is that software is so cheap to make, I really don't understand the world of investing in IT.