Depending on the game they kind of do.
There's trading and gambling on CS-GO skins, places where you can get real world money for them.
For games like EA sport games in their online competition thing, you need to have the best players in order to compete, therefore there's a minimum you need to spend in order to get those players. You need to do that in order to have a hope of winning competitions and earn some money.
So while you can't just cash out directly there are ways in which it can be done.
The thing with Magic Cards though is that when you buy a pack you still end up with a bunch of physical magic cards which you own and can do with as you please. Either sell them, trade them, give them away, or burn them in a fire. With digital goods from loot boxes this is rarely if ever possible.
Now ask yourself which would you rather have, something physical which you can do something with once you no longer want to play the game, or something digital which is useless and has no value once you stop playing the game (or even when next year's game comes out).
The thing with Magic Cards though is that when you buy a pack you still end up with a bunch of physical magic cards which you own and can do with as you please. Either sell them, trade them, give them away, or burn them in a fire. With digital goods from loot boxes this is rarely if ever possible.
Now ask yourself which would you rather have, something physical which you can do something with once you no longer want to play the game, or something digital which is useless and has no value once you stop playing the game (or even when next year's game comes out).