The Business & Economics of Scholarly Publishing - Why do faculty publish? To further research in their discipline, to bolster their scholastic reputations to be able to do more research, and to support their case for tenure and promotion.

CSU faculty do research and write articles that are subsidized by either the state of CA (through their regular salary) or by the federal government (through grants).
Libraries and the faculty and institutions they serve are participants in the unusual business model that funds traditional scholarly publishing. Faculty produce and edit, typically without any direct financial advantage, the content that publishers then evaluate, assemble, publish and distribute. The colleges and universities that employ these faculty authors/editors then purchase, through their libraries, that packaged content back at exorbitant prices for use by those same faculty and their students. This unusual business model where the "necessary inputs" are provided free of cost to publishers who then in return sell that "input" back to the institutions that pay the salaries of the persons producing it has given rise to an unsustainable system begging for transformation.
The subscription prices charged to institutions has far outpaced the budgets of the institutions' libraries who are responsible for paying those bills. Years of stagnant university funding and the economic downturn rendered many library budgets flat, while journal pricing continued to rise. This problem became known as the "serials crisis." Another element of the serials crisis that has been subject to discussion and debate has been the "big deal," which is when large commercial publishers sell their complete list of titles to libraries at less than what a la carte pricing for titles would be individually. Some postulate that the big deal has helped negate the effects of the serials crisis while others argue that it actually hurts more than it helps.
Over the years, librarians, publishers, scholars, and economists have debated the causes and status of as well as the solutions to the unusual economic system funding journal publishing and the resulting serials crisis.

Cited Source:

Rodriguez, J. C. (2021). Scholarly Communication: Key Perspectives. PowerPoint presentation to California State University, Los Angeles Department Chairs.