I have done this for many years. The problem is that software work is very similar to being a novelist. And very few successful novelists are able to crank out

I have done this for many years. The problem is that software work is very similar to being a novelist. And very few successful novelists are able to crank out lines of content for 8/hours a day. It is draining, but it is also work that can be leveraged by a huge amount. If a million people use my code or buy my novel, I have generated huge amounts of value. It doesn't matter if it took me 2 years to write the book or 1 month. I'm still able to make a living off of the revenue from that book. Same thing with code. If a software company is generating 5M a year you can afford to hire a team of developers to maintain it. Even if they are all not working 40 hours a week.