The Arcade Event page announcing the upcoming event with all the bundles was up long before the event launched. Riot caught a LOT of flack when people saw the pricing of the deluxe bundle and the page was full of people questioning it. When the event went live, there was another post announcing that they "mispriced it," though they also said they knew it was too much and adjusted it to be more friendly to wallets. To me, having a page full of players questioning the pricetag on a bundle before launch, followed by a reduction in the price of the bundle at launch indicates that Riot listened to players and fixed the problem people had. So yes, to me they were shamed into correcting it.
Regarding what you say about the cosmetics being paid and game being free, I understand that. However, events such as this are expressly for cosmetic content. There is no other reason for this kind of event. In that same breath, previous events such as this gave us daily missions for free, just like every other FTP game in existence. Therefore, comparing this model of the Arcade Event to the Order/Chaos event model and to the model of other FTP games, such as Heroes of the Storm, isn't a far cry, nor is it out of the ordinary. League has competitors, and when they severely bungle an event like this and lock the daily content behind payments that it's competitors don't (and hell, HOTS has daily missions at all times), it's bad for business and paints League in a pretty bad light. Its particularly bad for League because daily missions of a limited event by their very nature make the content you're buying depreciate in value every single day you don't buy it, and that feels pretty shitty for a player. You want the most out of your money, and if there is content that is daily that you didn't buy when the event began, you're on the losing end. It's a shit terrible business model for limited events, and that's exactly why competitors don't lock daily quests behind paywalls.