(from an old G+ post I found while looking through my G+ export)
For some people, the idea of progress in RPG design is threatening — they like the games they have, and they don’t want them to change.
For others, the idea of progress in games is associated with assholes using it push the games they like, or the games they are selling (cf Vampire in the 90s, much of the Forge crowd in the 2000s).
For yet others, they see the counter-evidence to any simple story of linear hobby-wide progress. For example, the recent resurgence of OSR play as a reaction to the plotted-epic-story direction D&D took in the 90s and 00s.
I think progress is possible, and is happening (on multiple stylistic fronts, which as S John Ross points out in [his now-unavailable G+ post] it must do). But I’m not surprised when people don’t believe in it, or don’t like the idea.