It may be better to improve yourself in the job you are doing than to look for a new job or do something else. This is not always true, but being good at something and improving yourself is always an advantage. Those looking for another job may be missing out on the opportunity to improve themselves in the job they are doing. This is a big deal in business and the economy, and choices can determine your future.
That's a good point. People should only lose focus on what they are doing for something else when they feel that they are not able to do what they are doing very well, but they can do better at what they are willing to do. If you know you can improve what you are doing right now, it's always a better choice to keep your focus on it and improve your qualities and abilities in what you are doing, be better than others at what you do, and you won't need to look for other jobs, you will be in demand if you are doing something better than anyone else around you.
It is pointless to leave one thing for another if you are average in both; this will only divide your focus, and you will eventually fail in both areas. If you are into something you are average at and want to get into something that you know you are better at, stop doing the first one and get into the second and have your complete focus on that.
Some people don't get it, but you can't be too good at something if you have your focus on other things as well. It's all about focus, will, and determination that can make you reach new heights in something you are doing.