I guess if you were looking at it from a purely logical standpoint, there's a limited amount of currency deluge (this is like the DNA of mobage) from completing content, so if you've exhausted that and are unlucky, you're kinda stuck with that hand while waiting for the comparitive trickle to come in.
Assuming you still wanted to play a gacha game, your options would be to either A) restart that same game just to see if you get a better deal out of it, progress/levels/etc aside, or B) start another game. And in that case A) would be a far inferior choice because you'd be retracing your steps compared to playing something completely fresh.
I think Brave Exvius' gacha is kinda messed up, but in a different way. If you've got time to burn and don't mind things getting a little grindy, Granblue has these deals that come by every month or so where you pop a 10-pull (money only, not currency) and get a pick of stuff out of a pre-determined pool of stuff - sorta like Beginner's Banner, but far more contemporary, and far more common.
Either that, or wait till Global gets the guaranteed 5* per pull - I don't think it'd be that hard to catch up to a respectable progression considering the way this game is designed - keep logging in for your daily mythril, maybe autobattle easier event levels, etc. till that point.
