My story won't offer any hope unfortunately.

I just retired after 20 years with a software company which is a leader in its field.

When I first joined there was no code ownership and despite my raising it often over those 20 years nothing had changed by the time I left.

My only suggestion is to work hard to gain a position of authority (which means not rocking the boat until then) and then use that to leverage the necessary change.

Rock and a hard place