If most of an ecosystem chooses a specific license (dual licensed in Rust's case), the simplest thing to do is choose the same license as everyone else.
Regardless of what others do, the best thing to do is to choose the best license for one’s own software. One which preserves the freedom of one’s users and the openness of one’s code.
Sadly people don’t always do what’s best. We sometimes do what other people are doing on the theory that maybe someone else has thought it through and already decided that it _is_ the best thing to do. It’s not perfect, but then heuristics rarely are. But it’s cheap to implement.
Considering how often MIT is chosen over the slightly simpler ISC version... yeah.
In the end, a lot of people are willing to write open source just for the sake of having it as it scratches their own need and isn't otherwise monetizable or they just think it should exist. I would never even consider touching a GPLv3 licensed UI library component, for example.
It's not always the most appropriate license and if a developer wants to use a permissive license, they are allowed to. This isn't an authoritarian, communist dictatorship, at least it isn't where I live and to my dying breath won't be.
Of course it's allowed. People can do whatever they want. If they think it over, consider the implications of what they are doing and decide that this is what they want, then by all means.
Choosing licenses due to peer pressure is completely stupid though. If you're not sure, you can just not pick a license at all. Copyright 2025 all rights reserved. If you must pick a license just because, then the reasonable choice is the strongest copyleft license available, simply because it maximizes leverage. The less you give away, the more conditions, the more leverage. It's that simple.
That people are actually feeling "pressure" to pick permissive licenses leads me to conclude this is a psyop. It's a wealth transfer, from well meaning developers straight into the pockets of corporations. It's being actively normalized so that people choose it "by default" without thinking. Yeah, just give it all away! Who cares, right?
I made some open source software myself and my desire is to see my code used as widely as possible.
So the ONLY reasonable choice for me is to release my code with a non-viral license. A copyleft license is TOTALLY UNREASONABLE for me because it limits the reach of my software.
Have you thought about it? If you have given it serious thought and decided that this is what you want, then by all means, go ahead.
The problem is that people choose permissive licenses to be "nice" when the truth is they have tons of unwritten rules and hidden assumptions. Magical thinking like "if I publish this open source software then it will come back to me in some way, maybe a job, maybe a sponsorship." No such deal exists. Then they wake up one day with corporations making billions off of their software while they're not making even one cent, and they suddenly have a very public meltdown where they bitterly regret their decisions. I've seen it happen, even with copyleft licenses.
When I publish something under MIT/ISC, it's generally, I wrote this to solve a problem/need, if anyone else finds it useful, cool. Use it for whatever you like.
If I'm writing something I intend or might intend to monetize later or otherwise don't want to have privatized, I'll probably reach for GPLv3, AGPL or a different license. The less "whole" a thing is, the more likely I'm going to use a more permissive license than not. Libraries or snippets of code are almost always going to be permissive at least from me. This includes relatively simple CLI utils.
This is gonna cause a lot of disappointment down the road.