From rubbish +‎ -ness.

rubbishness (uncountable)

1. The quality of being rubbish or worthless.
   • 2015 July 19, Eva Wiseman, “My mobile: so much more than a phone”, in The Observer‎^[1]:

     A Texan study earlier this year linked phone use and emotional instability, claiming that “incessant” checking acts as a pacifier, a distraction from the rubbishness of modern life.

• shrubbiness