Great assessment, Matt. I think your conclusions about why the ladder has become so absurdly hard is dead-on.
As more middle-of-the pack players realize this, I think HS will start losing its popularity. It may be pretty, but it just isn't fun.
I dropped it months ago and was not trying for Legend by any means. The ladder had become not only harder, but also increasingly boring. The meta becomes set almost immediately after a new expansion is released, and then it stays that way for months. There are easy ways for the devs to change that, but constant meta shifts would also disrupt their desired predictability for top names.
The devs are trying to hedge their randomness at the card level with a narrow, unshifting meta, neither of which is very satisfying (to me).