You would be surprised. Universities pay substantially better than newspapers (likely with better job security), and writing jobs are typically hard to find and low-paying in general. Many former experienced journalists end up working at university press departments because of the better working conditions.
From an enjoyment side, writing is hard, but for a lot of people, it's much easier than research. There are fewer credentials needed for a career in science journalism versus scientific research (a Bachelor's only versus a PhD for many senior scientist positions). I know a lot of people who have a natural skill at writing who decided to major in a science field for one reason or another, performed okay-ish at their courses, and tried to get back to writing work.
The end result is also similar writing for a magazine/newspaper versus a university. A university may have higher standards for accuracy and precision (especially if an interviewed scientist wants to review it, while a newspaper/magazine may have a policy to avoid sharing drafts to avoid bias in the article). However, higher-end magazines (like the New Yorker) have more prestige. There is also far less room at universities for dissent (e.g. presenting an opposing scientific view or publishing investigative work).
From an enjoyment side, writing is hard, but for a lot of people, it's much easier than research. There are fewer credentials needed for a career in science journalism versus scientific research (a Bachelor's only versus a PhD for many senior scientist positions). I know a lot of people who have a natural skill at writing who decided to major in a science field for one reason or another, performed okay-ish at their courses, and tried to get back to writing work.
The end result is also similar writing for a magazine/newspaper versus a university. A university may have higher standards for accuracy and precision (especially if an interviewed scientist wants to review it, while a newspaper/magazine may have a policy to avoid sharing drafts to avoid bias in the article). However, higher-end magazines (like the New Yorker) have more prestige. There is also far less room at universities for dissent (e.g. presenting an opposing scientific view or publishing investigative work).