If you're going to analyze a process you have to look at all of the steps involved, including waiting time, re-work or going backwards in the process/iterating, as well as the time to do the tasks. They all matter in the economics of delivery of working software.

The slowest part is going to be the parts involving humans communicating things to each other and iterating on the requirements and designs and the waiting times in between. The technical coding or generation of assets does not take that much time in the overall process.