Ray,

The decline in distribution is an annual pattern; views tend to surge during the summer months and decline towards the end of the year.

Medium sent an announcement saying that they stopped posting the "distributed" tag on stories. It's not that they stopped distributing things; it's that apparently they have shifted over to giving every story the "distributed" treatment, so labelling them was gratuitous. At least that's what they say. My experience backs it up, though; my last story was not distributed and yet has been one of my more successful ones, and its daily statistics show clear evidence that it is being distributed via Medium's normal channels in spite of the absence of a tag.

Good call on shifting over to Substack, either way, however. It's a good platform with a wide reach. I will be doing the same - the stuff I write there will be dual-posted on Medium as well.