Do Airshocks In An 07 Escalade Degrade?

[ihop]

my 07 Escalade has 78,000 miles on it and I'm not sure if the shocks are original or have been replaced. The ride is TERRIBLE, it feels like a boat. I don't have any error codes or leaks from the shocks but I'm just curious if they are worn out or not. 

 

Any suggestions for replacement? I think the only other replacements for the delphi shocks are the ones from Arnott Bilsteins which are 2 for 400 bucks...

[txab]

Shocks do wear out