Directly quoting the article:

> You’ll have to cleanly model the problem at hand and make each part of the solution easy to understand. Elegant code appears obvious, but it takes tons of thought.

Instead of future-proofing your code, the best thing you can do is write extensible code.

This means simple functions, well-defined classes, and comprehensive tests. In the future, when you need a new feature, it should be clear where & how to add it.