Earlier quoted context omitted.
Software is super complex and cheap to update. Engineering like this, however difficult, is not that complex and it's very expensive and difficult to update. We take advantage of the situation. If we invented some way of e.g. "growing" structures that turned out to be much cheaper we'd probably adapt our attitude to changing them.
When you say Engineering is not that complex, have you taken into account corrosive sea water, pressure, currents, what it means to make repairs and maintainance down there etc? It is difficult, because it deals with a very complex world full of physics, chemistry and even biology in a way that does not allow errors.
Engineering doesn't seem complex because there are centuries of learnings behind it. Those learnings become rules and suddenly it appears "simple" because no one debates whether to use wood or concrete when building an undersea tunnel!
