About 40 years' professional experience here, and IMO the article is spot-on.

The most critical aspect, I've found, is "keep up", which was driven home to me after Y2K, when I watched a lot of friends wash out of the field. In all cases, it was folks who had gotten too settled in their knowledge and habits, hadn't tried hard enough to learn the newer technologies and the changes in engineering approach, and found themselves unemployable when things changed suddenly.

So my rule is, spend an average of an hour a *day* on self-education. Learn new technologies, but also learn new processes and cultures. Never, ever, adopt an attitude of, "I'm more experienced, so I know better" -- while not every change is a win, every one should be listened to seriously, thought through, and understood in its context. An awful lot has changed for the better over the years; if you don't see that, you're not looking hard enough.

It's not that programming is only a young person's game -- it's that programming always requires a flexible and inquisitive mindset. Keep that outlook, and it's not too hard to keep going.