I haven't used GPT4 but my experience with Copilot is that it's just inconsistent. I think a big problem for me is I work in a legacy web environment with a lot of technologies that were never popular. So generating generic code that saves a google lookup is pretty good but anything more complex seems to be a waste of time.
The biggest successes I have seen are where AI does all, or most, of the work. I am not sure an AI could do my job but I do think, in the near future, AI could replace my entire team/department.
However, technology moves fast but business moves slow. I work for a pretty big enterprise that deploys dozens, if not hundreds, of web sites, apps and services. It's not like when AI becomes feasible, all of a sudden all of these things will be AI driven and there will be no need for any further technical expertise. Further, most businesses are not going to invest into a fanciful new technology with a proven cost/benefit model.