I never called it a disaster. I said financial disappointment. These are different terms with different meaning. You are changing my actual words to pretend I'm making a different argument.
Your point on not replacing Snyder completely overlooks the fact that SNYDER WAS REPLACED! The planned 5 movie series Snyder said he had was abandoned. The studio mandated a shorter run time not to exceed 2 hours. And the replacement director reworked the plot and changed the tone of the movie. Why do you think this happened? Do you honestly think the studio made these changes if they thought the BvS had met or exceeded their expectations? I honestly want to know what you think drove the studio decisions.
The last Batman movie prior to Batman Begins was Batman and Robin. The BO for Batman and Robin was $107 million domestic and $131 million international for a total of $238 million. Batman Begins had a BO of $207 million, $166 million international, and $373 million total. It was a clear improvement over the last Batman movie. Comparing Batman Begins to Batman (89) and only Batman (89) overlooks the fact that Batman Begins not only did better than the last Batman movie to come out, it also did better than Batman Returns and Batman Forever.
BvS had a budget of $250 million with WW gross of $874 million. The previous 2 Batman movies were The Dark Knight (Budget $185 million, WW gross $1.009 Billion) and The Dark Knight Rises (budget $250 million, WW gross $1.081 Billion). BvS had the first live action team up of Superman and Batman, plus Wonder Woman, setting up the Justice League team up movie. But it still had lower BO than the last 2 Batman movies. This is a financial disappointment. It is not a flop or failure because it did not lose money. But it did not do as well as the studio wanted.
This is not a criticism of the movie on any artistic merit. But it is clear that the financial performance of the series had an impact on the DC movies going forward.