> are trying to sell as meaningful improvements

There may not be "core" improvements (structural reliability) but there are "emergent" improvements (apparent intelligence). Already the IQ tests from Maxim Lott ( trackingai.org ) show a progressive sliding towards the right side of the curve - which btw translates to a very much non-secondary decline in the user's frustration (and progresses with an increase of usability).

The more they work on it, the more probable the jump becomes - e.g. to achieve the Large Conceptual Models you say you worked on.