Hotel devaluation is a fact of economic logic - most hotel programmes give out points based on $ spent, so as inflation pushes up room rates each year, the hotels are giving out more and more points for the same stay.

If 5 years ago a room was $100 (earnimg 10 points per $1) and earned 1,000 points in a scheme that needed 3k points for a free night, you'd get a free night for every 3 stays. If inflation has pushed up that room to $150 today, you'd get a free night for every 1.5 stays. The hotels have to increase the points needed for a night or it would be too easy to earn a free one.

The airlines, on the other hand, have no excuses, since miles earned are based on distance flown and not $ spent.