Limited budget doesn't say much, it's just an easy excuse to use at forums without knowing their actual budget, how they divided it among platforms or what perhaps went wrong. If your budget is so strict then don't release a PS4 version at all. But you want the extra sales without making the extra effort? (Is an increased resolution on better hardware really so straining on a game's budget?). Maybe it's a bug at release that slipped QA or they're already working on it for the first update, we don't really know. I just don't like the excuses. First it's Sony's fault then the budget that we don't know much about it and then something else.What part of limited budget you don't understand?
Personally I'm of the opinion that developer studios should be held accountable (in a civil manner) for issues. This is how they often get solved, just accepting things how they are won't do much.