Autodesk SketchBook went free – Why?

Autodesk announced the other day that their cross-platform (Mac, Windows, iOS, Android) drawing app, SketchBook, is now free:

  https://www.sketchbook.com/blog/sketchbook-everybody/

It had been a $25/year subscription, and seemed to be a relatively popular app. What does this mean? Is this a failure of subscription pricing, or were they just unable to compete in a crowded art market?