Funny. At 65 and retired, I still read in my areas of expertise (web design, UX, etc). I always did so throughout a 40 year career in journalism and then design. In contrast, at my most recent job I worked with a guy in his 30s who had ZERO interest in keeping current or reading outside of work. I could run rings around him mastering new apps and learning shortcuts and power user tips.

It's accurate to say it's a mindset issue, not a chronological one. Perhaps more people in their 50s and 60s have this mindset, but it's not a one-to-one correlation.