Thanks. Yes, you're right, sometimes "treadmill" is used pejoratively to describe forced upgrades that otherwise would be unnecessary. I was referring to the fact that we are all voluntarily installing security updates and/or improved versions of the software we use, year after year.
FWIW, I did pick up the pejorative connotation at first, but then realized it probably wasn't intended that way due to the complete lack of other negativity in the post.