tatement "You can't teach an old dog new tricks." Unless a person is used to changing, it's hard to change.
But for those of you who might be on the fence when it comes to the idea of working to learn something new, I offer this word of encouragement: Life is much like going to the gym. The most painful part is deciding to go. Once you get past that, it's easy. There have been many days I have dreaded going to the gym, but once I am there and in motion, it is a pleasure. After the workout is over, I am always glad I talked myself into going.
If you are unwilling to work to learn something new and insist on, instead, becoming highly specialized within your field, make sure the company you work for is unionized. Labor unions are designed to protect specialists.
My educated dad, after falling from grace with the governor, became the head of the teachers union in Hawaii. He told me that it was the hardest job he ever held. My rich dad, on the other hand, spent his life doing his best to keep his companies from becoming unionized. He was successful. Although the unions came close, rich dad was always able to fight them off.
Personally, I take no sides because I can see the need for and the benefits of both sides. If you do as school recommends, become highly specialized, then seek union protection. For example, had I continued on with my flying career, I would have sought a company that had a strong pilots union. Why? Because my life would be dedicated to learn a skill that was valuable in only one industry. If I were pushed out of that ind