No, devs being bad is not a solvable problem. You just have to find devs who know what they're doing, or at least have a few who can teach the less talented ones and check their work.
There is no programming language that you can't write slow code in.
Maybe in theory, but in practice I see it very rarely. Maybe it starts out great and fast and then devolves into a shitfest.
Given how frequent this is, maybe it’s time to actually blame the technology itself if it makes it so easy to mess up?