Airbus also functions very much like a quasi governmental institution in many parts, so there's less interest in squeezing everything to death to save money.
Finally, Airbus generally has a KISS mindset, and are very conservative w.r.t change in engineering practice and tooling. When I was there we spent way, way, way, way, way more time testing than writing software - and the software was written in a way that any software engineer could walk off the street and understand it.
Oh, and quite low levels of outsourcing in critical software - they save that for things that don't have people's lives on the line.
Amazing if true. One of the highest achievements in software.
https://www.gao.gov/products/gao-22-104480
See also this comment and answers: