Developers in the past were strongly for copyleft. The promise of copyleft is how we got all the great software that underlies the Internet today, starting with Linux itself.

The fact to keep in mind is that, despite what the name might suggest, copyleft is not at odds with copyright! The core feature of copyright is having a degree of control over what you have authored, and copyleft is ingeniously using copyright to prevent corporations from just taking open code, volunteer contributions, and modifying and using it for profit without giving anything back to the community.

Death of copyright would be the death of copyleft.