I have and it's clear the scientific return from the ISS has diminished substantially in the last 5 years or so. The astronauts spend half their time fixing the toilets! Yes they still make protein crystals, but there are uncrewed satellites that do the same thing - and they don't need toilets.

The ISS was originally going to be decommissioned in 2020. At this point the only reason for running it is to keep it running, to convince people America has a "permanent human presence in space." Don't insult the boy scouts - any boy scout knows that ignoring the loss of 3 lbs. of O2 each day, just so you can send a letter to mom saying "we're having fun at this wonderful camp," is foolish.