> That said, I've seen many really solid developers be motivated by solving complex technical challenges instead of work that actually creates business/product value.

Complex technical challenges create value for the developer, as it's fun solving problems like that. If management doesn't communicate the end-user's needs/wants and how the product helps them, even valuable work can feel like pushing up Sisyphus's boulder, so working on fun stuff at least creates value for you rather than work that appears to be purely for the leadership's vanity.