I came to exactly the same conclusion about six ago when I decided to try to get into the field. I spent several months studying and implementing all the common algorithms by hand and working on various public data sets. I enjoyed it and ML is a fascinating subject, but once I started taking a closer look at the job market I realized that even big companies only need a few ML experts and that those roles tend to go to people with graduate degrees in the subject. So making the jump from web or mobile dev, for example, is pretty tough.