Almost anyone can be a "builder" now. With AI, people can put together a website, an app, even a simple SaaS far faster than they could a few years ago. But precisely because building a product has gotten so easy, the software-engineering skill that keeps getting more valuable is knowing how to build a system the right way.
System design is the hard part to replace
To me, one of the skills that's hardest to replace in a software engineer is a real understanding of system design and software architecture. Not just "the feature works," but thinking through what happens when there are far more users, the data gets much bigger, requests spike, or the system has to stay stable while something is going wrong.
That's why interviews test it
This is exactly why system design shows up as its own section in so many software-engineering interviews. It reveals how you think as an engineer: whether you can only ship a feature, or whether you actually understand trade-offs, scalability, databases, caching, queues, reliability, and the architecture decisions behind them.
Where to level up
So as more people start building with the help of AI, engineers still need to level up here — system design and software architecture. If you want to start, I'd recommend ByteByteGo.com and Roadmap.sh. The material is genuinely good for building a more structured way of thinking as an engineer.