This is the way I see it.
If games truly become "incomplete" unless MTX and DLCs are required, I would expect all gamers to resist a game like that, and as such it won't be as good (and won't be as successful). The problem, however, is defining what "incomplete" means.
I see a lot of people say "If it's just vanity items, it's perfectly okay. But if it's some interesting story and lore components that I am really interested in, putting it behind DLC just makes me feel nickel and dimed." Which I think is somewhat ironic. It's like a request for us to make DLC that is less interesting and that people would be less likely to want to do something with. It seems a bit paradoxical, and it becomes difficult for me to disassociate it from a more general idea of "I'm a consumer, and prefer to get as much content as possible for as little cost as possible." Which is a fair viewpoint, and one I expect of all customers (for all products) really.
So to some, ME3 is "incomplete" without From Ashes or Leviathan DLC, because it contains story and lore content that people are really interested in.
ME3 IS incomplete without From Ashes.