The biggest impact individual developers can make on all the points I raised is to keep their own copyrights on copylefted works and do not sign an employment contract unless it explicitly allows you do to that.
Developers have more leverage in employment negotiation than they realize. Right now, most copylefted codebases that have historically had mostly individuals holding the copyrights are drifting to having companies mostly hold the copyrights. We have to stop this trend.
If individual developers hold copyrights, they make their own decisions about enforcing, and companies who oppose enforcement have less leverage.
Developers have more leverage in employment negotiation than they realize. Right now, most copylefted codebases that have historically had mostly individuals holding the copyrights are drifting to having companies mostly hold the copyrights. We have to stop this trend.
If individual developers hold copyrights, they make their own decisions about enforcing, and companies who oppose enforcement have less leverage.