Open source doctrine works great for the digital age but it does not apply to everything in life. It would not be a sustainable or practical system if every idea or product were not subjected to IP rights.
We see plenty of examples for why open ideas are good but that does not mean it works everywhere. This is a mind set that works particularly well with the digital age.
IP laws protect the rights of the creator from having their ideas copied and sold without compensation. But as I said previously, it ultimately comes down to the IP originator to determine whether they want to require payment or not.
Just because you wrote some code for a company that you work for does not mean you are entitled to the profits of every copy of that software. You assume a consistent paycheck and wage when you sign a contract. Unless that contract gives you rights to a profit sharing program then you don't have the ability nor the moral authority to reap the profits of the software you developed for your employer. It is common sense really and I'm surprised some people can't figure this out.
However if you are on your own and you develop software independently as Satoshi did then it is your choice to do what you want with it.