I think Let's Plays, or at least the type you described, started become popular once the Yogscast did. People were basically trying to copy them. Around the same time people found out that doing the same thing while screaming like a lunatic gets a lot of hits too.
I don't really understand the hate all these crappy Let's Play channels get though. Yeah, they are all just jumping on a band wagon because it's a piss easy way to make money, but the poor stuff can be easily avoided. They're not really hurting anyone who doesn't want to see them. You just ignore them. It seems unfair to say people aren't allowed do LPs because they're not good enough, people can do whatever they like. Eventually this fad will die down and the band wagoners will go away, leaving the good stuff left.
I don't really understand the hate all these crappy Let's Play channels get though. Yeah, they are all just jumping on a band wagon because it's a piss easy way to make money, but the poor stuff can be easily avoided. They're not really hurting anyone who doesn't want to see them. You just ignore them. It seems unfair to say people aren't allowed do LPs because they're not good enough, people can do whatever they like. Eventually this fad will die down and the band wagoners will go away, leaving the good stuff left.