I don’t get why big companys are afraid of open source software.
I know that monetizing open source is hard but in exchange they would have 8 billion programmers ready, for free!
Even if they do like redhat , as controversial as it is right now, they would be better off than just closing the source.
I would be willing to pay to have the license to modify my own software even if I couldn’t redistribute it afterwards.
Are there a lot of industries that would accept a piece of software that comes without techical support and/or liability?
What would happen is not dentists installing your software themselves, without support.
What would happen, and already happened countless times is that you see companies appearing that will sell services to install and maintain your open source software. It will be done by software developers just like you, except they can spend their whole time working for their customer instead of working on improving the software itself.
You will soon realize that you make money from the same activity as them, except you also have to maintain the software (and spent time to build it in the first place).
Of course you can use shady techniques to make it harder for others to understand your code, or release the open source version with a delay, but if you play by the usual rules of open source, with open development, third party developers will be able to acquire as much knowledge as you about the product.
Acquiring knowledge about the product takes time. Upstream has a better position just by being the one to create it and having all the knowledge about the product immediately, not after some time. Someone who decides to rebuild that would either have to fully maintain their own fork (and open source their work as well if the upstream has copyleft license), or upstream their changes, since reapplying bug fixes and new features requested by clients on top of the original codebase will take more and more time with each upstream change. Upstream can also restrict the use of their trademark, which would add a burden of marketing to downstreams as well.