The overwhelming majority of bachelor degree holders don't work in a field related to their major. Something like 30% of university graduates are working in a field related to their major.

That's fine, and it's always been normal. A university education isn't purely a vocational school, and generalized education is still very useful for navigating the world, including careers.

Most job fields just don't have a corresponding major. So much of the economic world is just administrative work, and the skill sets to be able to manage that are both universal across all job fields (using email and calendar software, word processing, the entire spectrum of skillsets for spreadsheets, maybe even basic scripting or programming, generally navigating through UIs of unfamiliar software or websites) or highly specific to one field and not necessarily learned in school (how to use a proprietary software product, or a particular piece of equipment invented long after you graduated from school, etc.).

Most jobs involve the intersection of two or more fields, and very few people will have majored in coursework related to both, and tend to have learned one or more of the intersecting fields well after they graduated, on the job or otherwise. Software sales. Aircraft leasing broker. Solar panel financing. Data journalism. One interesting area is that there are a surprisingly number of people who make the jump from oil and gas distillation/refining to becoming the master distiller for a major spirits producer.

There are really only a few dozen majors, but probably a few thousand career paths from there.