Insufficient context is definitely a major hurdle for LLMs when coding, but I think an even bigger hurdle is their inability to synthesize ideas and to resolve logical conflicts.

They don't seem to have a 'cohesive worldview'; additional context can easily sway them from one conclusion to the opposite conclusion. A large part of coding is about decision-making and prioritization; it's difficult to perform well at either of these tasks unless your worldview is internally consistent.