It's not all bad -- see the article.

But this is not good:

Airlines Have Been Getting Less Rewarding Over the Past Three Years

The combination of full planes and full hotels with the hangover of too many points printed in tougher times make for much darker times now. 

• Delta double-devalued its award chart and has gone revenue-based on the earning side and closer to revenue-based on redemption. They even dealt a blow to transparency (ironic since revenue-based should be far more transparent) by eliminating award charts and then they devalued again.
• United devalued their miles and followed Delta almost exactly with a revenue-based program.
• Both United and Delta introduced minimum spending requirements. Delta is going to even limit elite access to their extra legroom economy seats.
• American eliminated distance-based oneworld awards and international gateway stopovers, and gutted the double miles award. We then got a two year reprieve from major changes while the airline worked on merger issues.  But they’re going revenue based in late 2016 for mileage earning from flights. They’ve reduced mileage-earning on partner airlines. And they’re devaluing the award chart March 22.

There Have Been Bright Spots Even From the Airlines

It’s not all bad news. On the airline side Alaska Airlines Mileage Plan continues to offer outstanding value.