Before knowledge work was near exclusively performed on computers, it was not uncommon for people to preserve their own reference copy of work they had performed, and it wasn’t all that frowned upon.
Technology exists (for example DLP applied to endpoints by MDM) that enables the (at least ostensible or plausible) prevention of this but it mostly keeps honest people honest.
Because they are rational people who understand that data copied isn't a loss for them, and would rather attract more passionate leftists (if that's what your going for) to work with than people in a wage-slave mentality...
But everyone's going to do what they're going to do... regardless of if it makes sense or not, and having old (materialistic-centric) world views on digital content distribution is something we are going to have to learn to outgrow sooner than later.
Maybe it would jive better with the old school mentality if the diction of 'licensing to the employer' was non-exclusive as a default: resulting in higher wages where an exclusive license is actually required (or legal or moral/ethical reasons).
Being generally open about software makes the wages go up, not down. More of us get more done, faster, while exponentially increasing gains by contributing back. Open Source is the Way.
If I sell a book to Random House, Random House gives me money in exchange for the publishing rights to the book, but 35 years later under the copyright act reversion clause I can apply for the publishing rights back regardless of what the publishing contract says. Why would Random House agree to publish books?
The grandparent example gives Random House 0 years of exclusive rights, which means the author could directly compete against them from the start.
If an author can do a better job: the publishing house needs the run for its money... for it has gotten fat and lazy.
This would not harm MTV seeing as they were doing nothing with the content.
Because someone realizes of the power disparity between employee and employer, and legislates them into doing it.
Also, realizing that 99% of all code is useless out of context. The value of an e-commerce site, for example, isn't in the code itself that runs the shopping cart and website, but in the relationship with vendors and in the marketing talent to get your site popular compared to others.
What you're proposing is that you produce code, then your employer gives you money in exchange for use of the code -- but you also get to keep the code and do whatever you want with it? Why would an employer agree to that?