Most of those problems are due to the input/memory limitations for general use. I can imagine locally hosted GPTs that have training access to an organization's source code, development standards, and database data structures. Such a system could be incredibly useful. Human developers would just provide the prompts, supervise, approve, and test new/updated code.

Would have to be locally hosted, because most orgs are NOT going to feed their source code to an outside agency regardless of the promises of efficiency.