I agree with you that it's probably (past) time that real guns were used in any set. For those who insist on using real guns for realism, there should be safety protocols that are strictly followed and penalties for not doing so--even if no injuries result.If folks avoid the behavior for whatever reason, the likelihood of litigation is lessened in any case.
If the behavior doesn't occur, criminal prosecution is moot.
As things stand, I suspect Alec Baldwin will end up being liable for the death of Ms Hutchins and the injury to Mr. Souza, but not because he was the one who discharged the weapon that harmed them. Rather, because he's a producer on the film and the film had a history of unintentional discharges as well as a record of safety concerns--including some that were so severe that experienced crew members walked off the set.
Still, that will likely be a civil, not criminal*, matter.
*The caveat here is I am entirely unfamiliar with New Mexico laws so I have no idea whether there may have been any violations of New Mexico criminal law here. I am basing my conjecture in my understanding of most American criminal laws requiring some sort of an intentionality in the engagement of a prohibited act. Here, I'm not seeing where there could've been an intentional act that was prohibited.