1) software doesn't commit suicide like some pilots did.
2) software has superhuman reflexes, processing power and are not affected by emotion.
3) software also will eliminate a whole class of failure modes that caused many crashes in the past like: "I won't seek nearest and safer airport because that will be expensive in fuel costs"
4) software is already landing planes and saving lives in the process: https://youtu.be/XawXSLRCM3o
5) Most part of a comercial flight is already controlled by software anyway. Pilots mostly take off/land and input coordinates and altitudes.
6) push for fully automous aircraft during modern war is going to speed up development and test of the tech.
I think it's a matter of time here too.