I'm 41. Must make me ancient. :)

I completely agree with the OP. About 10 years ago I created a very focused professional blog to improve my writing even though I'd already written an O'Reilly book, just as an excuse to hone my skills.

I just created a blog series about building your own language in JS, just because I've always wanted to do it. There's definitely freedom that comes with age. (and goes away with small children)

https://www.pubnub.com/blog/2016-09-26-4-tutorials-create-la...

I've found that some good engineers find a role as developer evangelists, using both their technical and writing skills. Maybe check out DevRelCon.

http://devrel.net