I think your analysis is a bit outdated these days or you may be holding it wrong.
I am doing novel work with codex but it does need some prompting ie. exploring possibilities from current codebase, adding papers to prompt etc.
For security, I think I generally start a new thread before committing to review from security pov.
You can do novel work with an LLM. You can. The LLM can't. It can be an aid - exploring papers, gathering information, helping to validate, etc. It can't do the actual novel part, fundamentally it is limited to what it is trained on.
If you are relying on the LLM and context, then unless your context is a secret your competitor is only ever one prompt behind you. If you're willing to pursue true novelty, you need a human and you can leap beyond your competition.