I believe that the number 1 reason why a lot of peopel starting channels nowadays won't survive is because they are not taking it serious. I'm in the gaming upload portion of YT and it's SOOOO many channels that do what I do. But people are doing it just because it is the thing to do, it's the fad or trend. But unless you are willing to actually put hard work into making your videos AND networking and promoting your videos, you will most likely stay where you are with little or no growth. People walk into this BUSINESS without a business mentality. Sure it's fun and if you do it for fun, just don't expect to gain heaps of exposure and views. If you want that you must work really hard and keep up that work ethic. It's free to post on YT so sure a lot of people will do it, but the most successful run their channel like a business. So YT will never die because it's new people signing up everyday and some of them along with the established channels will keep driving and bringing in money.