happyhermit
Adventurer
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I haven't even tried yet to figure out what this even is (videos? podcasts?) but I'm guessing the "catch" is that these are decent production values and everyone has an angle - like the "serious RP" or "totally hilarious" or whatever? I do see the inherent worth of mixing game tables' gene pools: if I hear/saw a group doing something cool that might give me ideas, and so forth. Is that the main draw? Or just entertainment?
I think most people RPG sessions, while fun to play, don't actually translate well into entertainment (though I have enjoyed watching a table play rpgs before IRL). You are right in that to be "successful" they all generally have a good angle that fits their medium and target audience.
For example, Critical Role is the obvious top of the heap, their cast and GM are all voice actors, that is not something that "any" game group can just do. On top of that they had all been playing DND for awhile before making a show, and they are pretty amazing (Laura Bailey!) now they have great production values too. That being said, I never really could get into the show, partly because I always like to start at the beginning and partly because there were just way too many PC's for me, I think.
The opposite end would be when a popular youtube channel like sourcefed decides to play "DND". Production values were good, but the game was played horrendously, yet they still got 100-200 000 views. Probably due to the humour and appealing to their (young) fan base.
My favorite Podcast has been Critical hit and they are kind of a weird mix; excellent sound quality, good personalities, etc. They play 4e with minis in a very narrative game, which is pretty much opposite my preferred play-style but I love listening to them. However, had I started listening now (when they play on roll20) I probably wouldn't be able to get into it.
Just like anything youtube or podcast related (or singing, or pretty much anything really), anyone can do it, but making real money is another thing entirely.