It is very much an individualized thing. I have studied and worked in the career field I chose when I was 18 for 43 years and still am active in my professional society. My youngest son has a masters in business finance and he has changed jobs and employers, yet continued to work in finance. My oldest son is working on his PhD in wildlife science and loves that study and has worked several consulting jobs while in school. He will complete his program soon and should have no problems working in his field with the experience and education he has accumulated. But yes, I know a lot of people who have made mid career changes. Someone has to make a decision and go forward chasing their interests. In some cases those will change over time, while others will not. What else can you do but pursue your interests? It’s miserable to do a job you hate or find boring.
Edit: one last thought. It’s my observation that most people will change employers/jobs several times in their careers, but tend to remain in their broad career field, so education and experience aren’t irrelevant.