Standardised on what exactly? There are so many methodologies and/or tools, with endless possible combinations, each of which can reach the desired result in terms of functionality and even quality. And enforcing just one means no possibility of progress.
In physical engineering, things are very much limited by physical laws, which don't change (and even if our understanding on them might, that happens rarely enough to adapt). In software engineering, the foundational principles can and do change many times in an average engineer's career.
