MtG has a huge barrier you need to overcome to actually enjoy what you see. You don't have to fully understand LoL to enjoy the plays and the action at hand.
Plus, the format most people play is not even competitive.
Gameplay needs to focus on people not on the game itself.
this is kind of where i land on the issue. cost is a factor for sure, but inherently the game's learning curve is far more incredible to break through than others
a great illustration of this point is commander's popularity. you don't need to be following a metagame to really get into a commander video. if you enjoy the creators, you're gonna enjoy watching them shoot the shit more than the actual gameplay.
competitive magic is great, but it isn't flashy or easy to instantly digest at a glance. increasing costs are certainly an issue but even when it wasn't this bad, livestreamed magic content was still difficult to consume. i genuinely believe magic (and maybe all physical TCGs) is better suited for edited YT content