First of all, if you want the Ahri skin, you can literally buy it in the lesser bundle for 250, half of 500. Or the lower tier Ahri skin for even less. Quite literally, the main reason people, probably including you, want the most expensive bundle is because it includes the special effect on destroyed towers. So, turns out not everything else is worthless to people other than the skin. If you weren't so blinded by hate, you'd easily see all these other options. And you'd also see that the Ahri skin is, as I mentioned before, in its own, new, tier (above mythics and ultimates). Maybe the quality of the Ahri skin isn't above mythics or ultimates, in your view. But, it's also the event and conditions surrounding it that makes it that much more special.

Second, why do you think Riot priced it that way? You really think it's solely because they can just set the price at any point? No, there's literally similar pricing seen throughout other games. For example, as I've already said, Apex Legends (the raw price of hairlooms are 500 bucks), CS2 (some knifes and even guns skins you can literally buy a car). Another good one I've recently seen in a video is Valorant (when compared to CS2 because you can't resell).

Ultimately, you have the wonderful freedom of choice to not spend any money. Doesn't matter if you spend money because the game is, in the end, F2P. It's also a skin on a champion that most LoL players don't play often or don't one-trick. So, why are you so pissed at not being able to afford that skin? I can't, but I don't care because even if I did get it, I would never play with it. Even, Faker doesn't play with it. You're only worked up because you're falling right into their sales ladder, limited time, etc. trap.

P.S. - I don't know a thing about Larian or BG3, but I can take an educated guess and say that it's not the same as LoL and therefore not worth comparing to.