Everyone can play videogames but not everyone can be entertaining enough to actually get watched. Most successful video game channels that watch have either worked a long time to get to a position to actually make a living on YouTube, have established themselves as entertaining people in another format, studied/worked in a field that would make for an entertaining content creator or are just naturally entertaining. As with any art form, making a living on YouTube isn't easy nor is it reliable, especially with the constantly shifting rules and shitty decisions from the people at the YouTube HQ.