During the past few years some have asserted that the use of copyleft licenses, particularly the GPL, is in decline among FLOSS projects. While the data that is said to support this contention may be suspect, it matches my own observations and experience.

I examine why the GPL may really be experiencing some decline relative to noncopyleft licensing. Many factors are likely to have played a part, sometimes in contradictory or nonobvious ways, including the evolution of open source "business models", the nature of GPL enforcement and nonenforcement, the drafting of GPLv3 and its aftermath, changes in moral and legal authority surrounding the GPL, and general technological, cultural and economic developments affecting free software hackers.

If it is real, the GPL's decline is a problematic development for free software culture. I propose ways in which the trajectory of relevance and influence of strong copyleft can be turned around.