A show of hands of people who did not see this coming? Any time you turn your back on the people who made you popular you're going to see this. It's like radio turning its backs on the listeners. They've all found other things to listen to. And, surely, something else will come along to fill the void.
Youtube is very much like radio. You have to motivate yourself to stay fresh. In my mind I only have one viewer. It's nice to be popular but you can't associate your self worth with subscribers who can come and go at will. I make the same videos I did a year ago when I had 100 subscribers. If you let others choose the way you see yourself you will always lose. Don't let sub counts or views effect your opinion on your videos.
Everyone has a story. Because of different skills and various editing software we can make videos from "professional" content to just plugging in a camera and recording. To me the best ones are those who are being themselves. One of my favorite vloggers is Berehed. He's a unicyclist who loves what he does. Just fun videos that are real and honest. He has 30 subscribers and loves showing his latest accomplishment. I never miss watching video and I always comment.
The internet and those who use it is always changing. My experience is that you get out of the internet what you put into it. Make it what you want it to be.
(Barry Aldridge comments on this article and has some great thoughts.