Anecdotally I'd assume that intellectual curiosity often increases with age, although that might be attributed to the availability of learning materials now compared to years ago. Some people here on HN would likely be shocked as to how many people in the industry consume almost zero content outside of what is necessary for their jobs.
Seriously. People significantly underestimate how much better the average HN user is than the average developer.
The median software developer sees programming as just a job and spends absolutely no time on developing their experience outside of work.
I think it definitely does, depending on the person. Many, many attributes of the person change over time. That's what growth and evolution is about!
Some people take a career path where they become expert at a narrow topic. As they master their field, I think they lose a lot of curiosity because there's simply less to be curious about unless they're on the forefront of research and not just a practitioner.
Other people simply develop other life priorities.
It's 100% an individual thing.
Since for programmers at least, such information is not hard-separated from the course of their normal work, they will usually have the opportunity, if interested, to be at least partially informed about such things and have some sense of the overarching zeitgeist. For instance, a C# developer would be fully justified in reading about the changes slated for the next iteration of C# during his/her day job, especially as that iteration neared and achieved release.
On top of this, professional engagement and awareness IS something that deserves out-of-work nurture time, even when you have a family or other demanding non-work obligations. You don't have to have an impressive free time project like a hand-built CPU, but expecting someone to put in a few hours a month to tinker, learn, or explore new things related to their field is not unreasonably demanding IMO, even for experienced/busy professionals.
Obviously "participated in a MOOC [Massive Open Online Course, btw, for those curious]" may indicate curiosity (though it may also indicate someone trying to short-circuit their lack of skill by gaining Yet Another Credential to ride off), but it's far from the only signal.
The best employee is an experienced person who has retained their intellectual curiosity, even if they don't have the time to fully exploit it.