Hacking things together ad-hoc just to make it work isn't the way that clever programmers produce awful monstrous unmaintainable implementations. That's the way un-clever programmers do. Clever programmers, instead, invest lots of time into reinventing things that don't need reinventing, and then must be learned by those who come after them; and implementing things that don't need to be reimplemented. Reams of copy-pasted code is not the affliction of the clever programmer. Instead, you discover that there's a strategy factory to instantiate a strategy that chooses which home-grown database abstraction layer to use and what kind of caching to apply to it; and that there's a home-grown template library on top of that, with its own caching layer. And it's all configured with a plugin system that uses a bunch of XML metadata files for each plugin — all in order to run a message board.
Being clever shouldn't mean that you're hacking things together ad-hoc just to make it work. On the contrary, that is the opposite of being clever.
I really doubt that most of the bad code is written by "clever" programmers. Other factors are at play here.