IMHO AI will be able to generate solutions close to the best solution for a problem, with the remaining distance to be covered by humans.
the question is whether the cost of using AI to generate a solution, and then fixing it manually, will be lower, or higher, than building the solution using humans.
as we have seen before with wizards and other tools to generate solutions, the cost of fixing the solution is often times higher than it is to just build it from scratch manually.
also, as humans use AI more and more, there will be less and less material to use for training that is high quality, and AI will train on itself, leading to a rapid decline in quality of the output.