March 28, 2013 Hilton did a 90% devaluation for many of their best properties. The top non-Waldorf property was category 7 and cost 50,000 points up until that point. On that day Hilton Honors moved to 10 categories with redemption prices ranging 70,000 - 95,000 points.

So that's not a 100% devaluation but for many properties it was a 90% devaluation in one shot, and that's when they were more transparent and still had published award charts. So I wouldn't say never...