> It does feel a bit like building on quicksand

that's a good analogy and puts into words the way i've always felt about software development. Every so often the entire industry rolls over into something new. I've been here 30 years now and, in my experience, the skill that counts is being able learn new skills. To go back to the analogy, to build something new on top of what you've built in the past before everything is swallowed by the quicksand.