>executing large-scale changes in entire repositories in 3 years

You can look at SWE-Agent, it solved 12 percent of the GitHub issues of their test dataset. It probably depends on your definition of large-scale.

This will get much better, it is a new problem with lots of unexplored details, and we will likely get GPT-5 this year, which is supposed to be a similar jump in performance as from 3.5 to 4 according to Altman.