I often see the argument that people who write the code should do the architecture as well. Maybe on a small development effort it can give better alignment.

I often see the argument that people who write the code should do the architecture as well. Maybe on a small development effort it can give better alignment. When things scale up and in bigger orgs though, it doesn't work nearly so well. There are so many different business and technical requirements and strategies to take into account and signed off. This is a full time job. It may lead to really annoying things being imposed on the developers that they would never have chosen. However, this does not mean that the architects are idiots, although that is of course possible!