Louis Rossman has testified to Congress on the matter.
There is no sane reason to use government enforcement to stop people from tinkering with what they own. The only legitimate reason is an end state that is illegal for good reasons like removing a catalytic converter.
If just 20% of prospective buyers devoted 1/2 their budgets to a common open solution, they could break out. If there were a tiny company offering an old school model with modern features at a competitive price, that would be enough. Then, if farmers choose to lock themselves in, it would be a real choice and their own fault.
BSD didn't need legislation. GNU didn't. Windows still thrives, but people have a choice. Just convince ADM and a few others to throw some pennies at a startup. Except that the new licensing greatly benefits those giants. So you'd have to convince 100s of little guys to throw big money your way.
They absolutely did. Both depend on copyright. GNU licenses in particular were created in reaction to copyright protection being extended to computer programs as if they were literary works. Today, all of free and open source software directly depends on copyright in order to even be recognized as such.
Right to Repair legislation goes 90% of the way to stopping the lockdown of the machine internals and codifies for everyone that once a machine is sold and in use, the manufacturer no longer has control over that machine.
Without the law your open source software would be blocked by DRM and I am sure the companies would attempt to void your warranty if they can find you modified anything.