Privilege
Though commonly cast as attractive villains on say, Law and Order, being wealthy neither males Baldwin directly cuplable nor "privelaged".
I am thinking that actors (whose level of familiarity with weapons varies immensely) are told not to attempt to check the weapons handed to them- a very dangerous act if done badly, but to trust the professional armorer.
Thus, Baldwin, his wealth aside, did just that- he trusted the armorer. Likewise, the fact that armorer is likely far less wealthy than Baldwin does not excuse her from primary responsibility.
In the end, Baldwin's responsibility seems pretty distant. He apparently had a part in funding the movie. As a result, he arguably had a responsibility to inform the other financers that things were going badly on the set regarding weapons and that either the armorer, assistant director, director- or all three should be replaced.