At this point of popularity, buying the game or not does no difference to the future of those games. Millions will buy them. It's like being Pro-Sanders, but refusing to even look at a picture of Hillary on the net. What does that do? Nothing, the picture already has millions of hits. Or, an Adam Sandler movie. They're absolute garbage and insulting, but many know this and go because it's a 'popcorn movie'. Or the Star Wars Prequels. ETC. Same with Fallout. No matter how much you hate 3, or 4, or NV, it was financially successful with or without one buying it; they'll make more games on THAT fact and nothing else.
So, why not buy them and play them and *know* what it is and make an informed opinion thereof? There's no harm. I played Fallout 4. I thought that, even though they use the BoS and Mutants again and whatever, maybe it'll be fun. Hell, the Minuteman faction, while expected, was refreshing, and even though it was far from a good dungeon crawl, destroying the institute was primal and momentarily fun. Etc, etc. By the time I played it, around what - 3 million copies were sold?
Not playing it would had just made me an uninformed wanker complaining about something I would have no experience about. Playing it would make me an informed complainer. The latter is unanimously better than the former....