Specialization in a certain field/industry narrows your job prospects and opportunities. However, learning a wide range of skills allows you to get involved in a multitude of jobs and investment opportunities, so you can make more money and become rich.
Seek work for what you will learn, not what you will earn.
What skills do you want to acquire before choosing a specific profession? Look for work that will teach you those skills.
If you do become highly specialized, seek union protection.
If you are pushed out of the only industry you have the skills to work in, you will have a hard time finding a job that pays equally well. So, seek union protection.