It's a cultural thing mainly. Things like rust and npm came out of the "Github generation" of open source developers which trend towards permissive licensing, in part thanks to Github's own anti-copyleft bias. Github's founder openly advocated to "open source almost everything" (the "almost" part being "core business value"), arguing that open source serves as a foundation upon which to build proprietary products. In this world, participating in open source is merely a way to gain PR and volunteer labor for the proprietary product.

I'm not automatically opposed to permissive licensing (nor is FSF/GNU, in fact!) but in making it the norm we put proprietary software companies in control of what ultimately becomes available in the commons.