It's not really gambling at all though is it, since as you say 'the house takes 100%' - there's no expectation of (any chance of) profiting from it. It's dumb yes, but it is just paid entertainment; we don't say paying Netflix is gambling ('some months we don't even find something we want to watch!') for example.
I mean, many lootboxes contain things that can be resold for profit... It's just that game devs don't have to "pay out" the winnings, more consumers do. CS skins are the most obvious.
Gacha is definitely gambling even if profit isn't the primary motive. You could argue that profit isn't even the primary motivation of many poker players, but rather being seen as smarter than the next guy or more able to call bullshit.
It’s not even close to Netflix . You paid a 5$ monthly FIXED fee and can watch everything.
Loot boxes on Netflix would be, you have no movies when you start:
You pay 2$ to add Random 3 movies to your library.
Wanna watch Breaking Bad? Pay 2$ until you get “lucky” (and maybe get only Season 3).
Ah, and maybe because it’s premium show, there is only 0.5% chance of getting it in every “loot box”.
So you might spend thousands of dollars, and not get what you want… Because usually there is not even a way to spend 10$ to buy it like a movie on Aplle/Amazon, you have to gamble!
It's not technically gambling, but it's every bit as insidious and preys on the exact same elements of human nature, except we allow it to happen to children.
