Not to mention the fact that if everyone else is getting a solo movie it only makes sense for Batman to too.
The same goes for Black Widow, but she hasn't gotten a solo movie yet...
MCU wont give her a solo film. its harsh but its a reality. Hollywood has hardly produced successful action female heroes and I am not talking of hunger games.
After the failure if supergirl ,aeon flaux and Electra. MCU is not confident enough...YET.
They're confident enough for a Captain Marvel solo movie, a character they haven't even introduced yet. Same for WB/DC and Wonder Woman.