Graduate student unions aren't aiming to tackle this, and I don't know of any that are. At Stanford, the unionization campaign centered around Stanford's stipends (which have not kept up with inflation and put students in the "extremely low income" category per the county) and Stanford's status as both employer and landlord for many students.
It's pretty much the same at all Universities in HCOL areas.. UCLA is the same. UCLA actually had to build graduate student housing to offset the market and it is still overpriced. Talk about levitown.
