All of these things you've described are actions taken by someone that has not had a deep think about their code and organization, architecture and patterns. It reeks of inexperience, and/or pressure to get shit done without needing any time/deep thinking on how best to do it.

While the teaching is partially to blame, i say it is more that most people are sloppy and undisciplined thinkers. When they dont have any incentive to produce disciplined code, they wont.