It's a slippery slope made from casualization and greed.
On one end companies started catering to the lowest common denominator. You gotta get those sales numbers if you wanna secure a bigger publisher deal, and a bigger deal means bigger games, which means more sales! It's no surprise that every big company tries to chase down this shit instead of being content with where they are.
On the other side, we also have the free to play market. Despite what you may believe, the free to play market is not a recent thing, it just got really big recently. Around the 2000's is when Runescape, Maplestory and so on started popping up trying to make money off of micro transactions and optional subscriptions, and it kind of worked.
Back then, I think pretty much everyone in the gaming community recognized that free to play games presented a case where the quality of the game is highly dependant on how the game's payment model interacts with the gameplay, which is why there was heavy pushback for anything more than Runescape's subscription model. (Which, for clarity's sake: Went out of its way to avoid pay2win bullshit. Although the extra spots to collect certain materials in the subscription area's was an advantage, certainly, it was also the case that many of the items you could obtain were unusable in free2play servers. You cannot pay for a subscription, get a high level weapon and then go dunk scrubs on the free2play server. This is why people did not mind as much.)
Problem, though, is when the gaming market started becoming more casual.
The more casual a market is, the less people actually care about being screwed because "I'm having fun so it doesn't affect me".
Then you can slowly introduce slightly more jewish bullshit into the game. Every time something new comes in, some of the old core playerbase leaves, but the sales made by some of the casuals then take their place. First its stuff like double XP and drops, then we get cosmetics that look wacky and completely out of place, then eventually people introduce exclusive content. Exclusive content gets followed by season passes because then "you're getting a better deal!", and so on and so forth.
The newest cancer that's seeping in is paid mods. First volvo tries to push paid mods into an EXISTING modding community, even going as far as to say it's okay to repackage other people's free mods into your own mod and sell it, and a backlash happened. Great, they stopped being retarded, but that was only briefly. Paid mods are ALREADY BACK, and without a backlash to stop it now it's slowly seeping into dota 2 arcade and fucking everything up. It is already the case that there's popular dota 2 custom maps where you can pay for an advantage. Nobody's complaining loudly enough, so it's just gonna stay, and it's gonna get worse because money.
As for your case:
I think that's because you haven't played free to play games at all. If you played those you would understand that cosmetics aren't that big of a deal if you at least got something back (a free game!) for it. Unfortunately we can't have free2play games without jew2win mechanics anymore.