I am glad you wrote this, Randy. I pretty much agree with what you say about attention spans shrinking. I used to love reading novels, and was often attracted by how thick they were, as long as it was an author ai liked. The bigger the read the better.
But now, I rarely read a novel and if I do it takes me months to finish.
On Medium I specifically look for items between 1 and 5 minutes reading time. It depends what type of writing it is, poems tend to be on the shorter side. I tend to avoid anything over 7 minutes entirely, no matter who wrote it. I would rather read the work of three or four others than spend time on one really long article.

Myself, I like to try to keep my writing in the 2 to 5 minute range. Under two minutes I feel like I am cheating the reader, but over five I feel I will be testing their attention span. This is why if I write a fiction story I also usually try to make it flash fiction. I love that genre more than any other.