There is a surprisingly large community out there of commercial pilots who are also software developers. The software side is usually a hobby for obvious reasons, but I know a guy who is a Captain for BA who is big in the .NET IoT community, maintains a bunch of projects, speaks at conferences etc, and he has many friends / contacts who are also ‘pilots who code’.
There are bound to be controllers out there who also code, but you’re right, the very best way to build highly domain-specific software is to put together great software developers and domain experts on a dedicated team.