Have you ever spent two years pouring your heart and soul into a project that only three people will ever see? In academia, we call that your “dissertation.”
Philosophers spend a lot of time writing things and trying to get them published in journals nobody reads — not even other philosophers — because in order to get a job, you need to have these papers and journals on your C.V.
Those two years you spent every day working on that paper — all that effort reduced to a single line on a C.V., just to ever-so-slightly improve your odds of getting a good job as you compete against people who also have those lines on their C.V.
Nobody reads this stuff because most of the journals are behind paywalls so expensive that only large libraries at academic institutions can afford to access them (and even then, many university libraries are cutting some journals off for budget reasons). Even within the halls of academia, where people do have access, there are simply so many papers published every year, even within niche fields, that nobody has time to read anywhere close to all the papers/books being published, especially considering the amount of reading it takes just to teach classes, etc.