By that reasoning MCU would never have existed...
Even if BvS underperforms there's no going back.
Will WB be sad that they didn't make more money. Likely.
Will they scrap their future plans because of it. Highly unlikely.
The next two films are Suicide Squad which has generated a lot of buzz even among people who don't watch comic book movies , and Wonder Woman who was a highlight of BvS even for a large number of people who hated the movie. Both have a good starting position regardless of BvS backlash.
I don't see them backing out of Justice League neither, it starts shooting in the next few weeks and is reportedly lighter in tone. Risking another underperforming movie is still financially better than delaying their entire slate.
People said that about ASM2, especially because it was going for spin off movies. I think they have too much invested in it, but I personally think two awful awful movies in a row means they have a hell of a time salvaging it. Two movies in and they've completely missed the point and essence of the characters. Can you realistically salvage a Batman who callously kills and comes across as a fucking lunatic? Or a Superman who appears to be at the end of a typical Superman arc in his comics? Wonder Woman was -okay- but I think the casting of a woman who can barely act to lead what you hope is going to be one of your main franchises is already going to kick their ass.