Point devaluation is relative to your travel pattern and earning methods.

2009 Marriott Rewards introduced no blackout dates and eliminated Anytime Rewards, but also eliminated its progressive discount for longer stays. The cost of hotel rewards for 4 to 7 nights increased from 25% to 60% for hotels in category 5-8, unless you are staying exactly 5 nights.

Point increases also happened for Marriott Vacation Club and Ritz-Carlton extended stays.

Hilton, Marriott, Starwood and Hyatt have all shifted more properties to higher category levels costing more points for reward nights using points.

Programs have reduced the number of hotels and/or dates available for discounts like Marriott PointSavers, HHonors PointStretchers. Difficult to determine if availability of SPG Cash & Points has changed significantly since there is no master list.

Priority Club Points & Cash and HHonors Points & Money are two consumer friendly changes increasing point value.

Hotel loyalty programs are dynamic systems and the seasonal promotions tend to be the main difference improving the value of points by making it easier to earn points through hotel stays and open access to higher value rewards at higher point costs.

The reliance on hotel loyalty co-branded credit cards reduces the value in every program for members who earn most points through hotel stays.

The overall growth in points liability from credit card earning leads hotel loyalty programs to lower the value of a hotel point overall in redemptions.

In general hotel points have less value over time as the cost for a free hotel night increases at the majority of hotels each year or two.