Mostly all of the responses in Reddit (and other places) are just, plain stupid. Majority of the comments came from the Europeans, thinking the MTX are "illegal". However, they forgot that this is the norm now at days. Ignoring MK1's shop BS and limitations, SF6 didn't give that much slack until the TMNT collab (and also the Costume 2 can be obtained by grinding in World Tour and that doesn't take long, except for characters like Juri and JP). It could be true that Bandai Namco avoided mentioning about the Tekken Shop, although, some people stated that it was mentioned before release, but it was still on the works and many listeners/readers ignored it. Also, the things about development and costs for optional items: well, you can say that the Tekken team were focusing on the gameplay, designing, graphics, story, character roster, modes, coding, networking, QA, and other things that are part of game development while customization were like the bottom of the barrel, for both the characters and avatars.
Me, however, I don't care. Call me "whale" (which I'm not!!!), but I want to support the game. You think Season Passes only gonna help with costs and development for more DLC content? MTX would benefit so we can get more modes, characters that we wanted/should be in the roster like Anna, Julia, Armor King, Michelle (I'm wishful here, but she NEEDS to return!) etc., stages, and other QoL stuff in the future. Without that, you can kiss Tekken 8 goodbye in the next year or two like Soul Calibur 6.
Oh, I forgot to add this: people complaining about the MTX "real currency" thing when it is not just developers/publishers like Bandai Namco, Capcom, etc., involved. You also have to include the consoles and PC providers too (Sony, Microsoft, Nintendo, Steam, etc.) because they WANT their fair share too! Capitalism at its finest, people (and taxes!)