As much as I love Boston, SF is not the only other city in the world, and both cities are extremely atypical. The graduates are likely leaving for a place where they can get a $49,500 salary and a $700 apartment.
EDIT: and your percentages are wrong: try 48% of gross for BOS and 60% of gross for SF. Figure 40% for taxes and you have either very little for food, insurance, medical care, transportation, clothing, entertainment or you're already negative. Oh, and I forgot: STUDENT LOANS.
EDIT: and your percentages are wrong: try 48% of gross for BOS and 60% of gross for SF. Figure 40% for taxes and you have either very little for food, insurance, medical care, transportation, clothing, entertainment or you're already negative. Oh, and I forgot: STUDENT LOANS.