Lets take banks - knowing how banks work in general means little for that one specific bank who is paying you, which has different portfolio than most, different processes because everything is homebrew over decades of doing business and they differentiate from rest of the market in many ways and thats their key proposition, different data infra, set of internal apps, protocols and so on. There is no general llm knowledge you can distill in few minutes that would help you much.
You need to know your specific company, no way around it. In fact, to be proficient in those deliveries, you need to know those internal politics, processes, their quirks and so on, 100x more than some code fast delivery since this is majority of any bigger project. You need some reputation to get things done effectively.
This, for some time, won't be something llm can massively improve, unless those companies change themselves.
Of course there are ways around it. For example you can build the foundation yourself (which will cover the 80% that is shared across every company in that industry) and give users the ability to build the rest themselves inside the software. This type of abstraction-based architecture is how platforms like Salesforce took off and became ubiquitous.