If you abolish copyright, that will only make it easier for for-profit corporations to use FOSS. There will be nothing stopping them from using FOSS, unless people stop sharing their code altogether.
While True, if you abolish copyright then there is nothing preventing me from Installing Microsoft office on as many machines as I want never paying Microsoft a dime....
This is a common misconception: without copyright, Microsoft would still have many legal means to force you to pay for every copy of windows, from contract law to patent licenses. Without copyright there would not be free software and copyleft as we know it.
There is zero mechanism under patent law to enforce what you are referring to.
Patent law is about selling items not consuming them so they could prevent me from selling a clone of office but they cannot prevent me from installing office
as far as contract law that would be between two parties so if I obtained a copy of office somewhere and I did not have a contract with Microsoft nothing I would not be violating a contract with Microsoft copyright is the only mechanism they use to stop unauthorized distribution of their software