So have I. In fact, most of the "can't do" folks in their 20's and 30's that I've had to deal with were failing to solve easy problems. My peers and I had encountered these in the past, we had solved them, and didn't care to waste time trying to come up with new solutions to them. The ones who failed were too arrogant to listen to the voice of experience, and as a result they failed miserably.

That said, I've also encountered peers who were too set in their ways to change, and continued to fail in almost exactly the same way over and over again, refusing to learn from their own experience.

It goes both ways, but age has had very little to do with it in either case. It's usually been arrogance instead.