It's about expectations, Zaslav's, nobody else's. We've seen this with other movie studios. ASM2 made similar money, but wasn't up to Sony's expectations. BVS made more money, wasn't up to WB's expectations.
Zaslav might want Batman 2 to be a mass appeal movie and be the centre of a DC cinematic universe, while Reeves could just want to just make a true sequel. That is a plausible scenario now.
ASM2 and BvS were very different situations.
First, neither were made in times of a global pandemic and a certain country in Eastern Europe trying to invade Ukraine which...kinda tends to gut profits like a fish.
Second, ASM2 was a sequel which made less than the first movie. Hence the disappointment. The Batman isn't ASM2 in this situation, it's ASM1. A good profit, with theoretical potential for much more. If Batman 2 doesn't do better,
then we're in trouble. I'll admit that much.
Third, both movies had higher budgets. Both have their budget range top out at 100 million more than the highest of estimate of what The Batman was made for (keeping in mind the budget was almost certainly inflated by COVID-19). Therefore, 700ish million is obviously less of a profit than in the case of The Batman.
Fourth, both movies had
far longer release windows. Both ASM2 and BvS were in theatres for three months. The Batman was in theatres for 45
days. And while just beating ASM2 and falling a hundred million short of BvS, it had a higher domestic gross than both of them.
Fifth, BvS was expected to break the bank because it was a milestone. It was the first live action movie with Batman and Superman in it,
ever. And it came out 4 years after TDK trilogy ended, which did break the bank. The Batman was a near 3 hour long reboot and the first Batman solo movie in 10 years. It's a pretty big difference in context for both movies