>>43343704fa/tg/uy here. this is why
1) Requires a set schedule for streams. Real player games have enough of a problem with this, let along streamers all trying to work out time zones.
Only real work around would be have a one off game but again, it requires that all members can attend.
2) Learning a system. Even the easiest ones require people to commit and know basic mechanics; otherwise it grinds game play to a halt.
3) Interest in the setting. You need enough people to be actually be invested in playing the game and not just 'go through the motions', otherwise they'll drop out. People think TTRPGs are boring/cringe to watch? Imagine being forced to sit there and play something you've lost interest in or just not feeling. If the players/GM are not having fun, its easy to tell and makes the watching experience as bad for the viewer as it does for the players
This is why Mythbusters fell off and why Mori said its not going to come back.
I wouldn't hold out for Tempus' DnD game to come back anytime soon either