Not a fan of the black or white perspective on this.
For instance in some companies there is only one engineer…
But in a larger org with many engineers code ownership is still a good thing as the person that writes and maintains said portion will understand it and be able to debug and add features to it faster..and continue to follow the design pattern AND/OR quickly see that now is the time for a quick refactor etc.. As opposed to a new developer that has never seen this code who will likely just find the first place he can add code for the desired outcome…←- that is the path to spaghetti code.
Also being an owner doesn’t mean you are trapped and can’t grow.. it means that when there is an issue with code you wrote it is resolved quickly and with less frustration than if you put a non familiar developer on it.
Once the owner knocks off the simple task he goes back to his new feature or whatever bug he was working on…
And lastly you can’t expect to get all of your personal growth in this industry from work only. I know people hate to hear this, but the best engineers almost alway’s have hobby projects or maintain open source applications, etc.