The control system and sensors algorithms would be developed by engineers (not software engineers). Then implemented by the software engineers. That is subsequently tested again by the non software engineers. It often auto coded from simulink models, requiring less input from software teams.

Most of the software development done by software engineers or developers in aircraft is scheduling, connecting pipes, data recording, networking etc. Keeping the aircraft flying is done by other engineers. These algorithms are more related to aircraft dynamics, electrical systems and sensor physics than algorithms used in software. Most control systems implemented are represented as analogue electronics, even when the engineers have only ever used digital systems for their control. In these cases knowledge of non-software topics are more important.

So it would still be people with degrees keeping the aircraft in the air. However, many of these roles could be accomplished by people who have non university qualifications or 4-5 year apprenticeships. But it's hard to teach the background maths involved during an apprenticeship as it's not being applied day to day and the other engineers skills may have atrophied compared to a university course. Degree apprenticeships do work well for this sort of thing.