My understanding of that article was that it was not necessarily about duplicated code, but duplicated data. If you have two places storing the same data, and different parts of your app go to each of it, you need to somehow keep them in sync, and that’s often a pain.
I’m trying to be very rigorous about avoiding that, duplicated code I’m a bit less rigorous about.
If you are concerned about environment, maybe look for companies that make software for public transport. DB Systems, Init Group, PTVgroup are some companies of the top of my head. DB Systems is not the best working climate (or at least used to be, I had someone close to me work there and they hated it a few years ago).