More importantly for businesses, the results developers produce can be insanely valuable.
It can free businesses of their primary constraints, enable or support economies of scale never seen before, create entire new industries or replace less efficient, higher cost or broken industries.

Companies need to pay people, who understand not just computers but also the business environment around them.
It is these rare people who can interpret the human and business worlds in a way that computers can operate.
This resource is not a normal programmer and it is a scarcity, especially given the emerging potential of automating everything across every industry.

Nobody is going to pay millions to have holes dug if there is no gold, and they aren’t going to pay for highly skilled teams to automate our lives and then continue to improve on that work without a return.

The majority of all software projects still fail these days. Who is going to take that sort of risk if there isn’t going to be a carrot at the other end?

Open source is great, it helps our industry move forward but its not the only piece of the puzzle.
All of the example open source companies are “software for technical people”.
This is because they are solving their own problems, not yours.

The rest of the world “software for *your* industry” isn’t going to be open source because your industry can’t solve their own problems. You have to employ techies and focus them on solving your problems, you have to accept the risk (and you will want to take the rewards as well).