The problem is that open-source purists the likes of the Free Software Foundation have and continue to maintain that FOSS doesn't have to mean
gratis, that there is supposedly some kind of reasonable path to being able to feed yourself while working on FOSS.
There is an idea pervasive within the developer culture that--through sweat and grit--one can build a project (regardless of FOSS or not) and eventually be recognized for the effort. And not just recognized, but recognized in a specific way. For some developers, that is notoriety. For others, it's money. But the idea is basically "my code in -> my definition of validation out".
And I think it's pretty clear that, for most projects out there, that's just not true. Or, more specifically, there is a huge chunk of the story that is missing. Because it's not hard to find dozens of projects in almost any niche, across thousands of niches. For the vast majority of them, they toil in obscurity. Some of them might be underdeveloped, but I see that more as a result of the failure to receive said validation leading to quitting the project. There is clearly some other factor involved in between creating a project and finding success with that project.
A lot of that missing element is selling. Even FOSS projects that are delivered free of charge to users need to "sell" themselves. Linux wouldn't be anywhere if Linus Torvalds hadn't recruited users. You have to convince people to try your thing and that convincing can take many forms. "Selling" is putting a name to "the act of convincing".
It's not quality code. It's not documentation. It's not a pretty website. Lots of failed projects have those things. Lots of successful ones don't. You have to market your project, and that's work.
Work that isn't coding. And that's why more developers don't do it.
Celebrity developers have people hanging on their every word on Twitter already. They have already done the work of advertising--advertising themselves--and now they cash in on the reputation and can make a successful project just by announcing it. Large corporations have money to pour into actual advertising and marketing for new projects. But independent developers don't have the cache or the money to be able to pull that off, and don't have the visibility into the background work on those other projects to know how their efforts are different from the projects they look up to.
But FOSS advocates keep pointing to the work of celebrity developers, of "open-source aligned" corporations, and saying "see, open-source can work". There's a lot of pressure from other developers to open your work. Most of the loudest voices keep saying, "this path works", leaving out the key element, making it sound like a dream.
I call this the "Field of Dreams Paradox". We have the phrase "if you build it, they will come" stuck in our cultural memory, but have forgotten that the movie is about a literal miracle.