I have a couple comments here. First, forget starting salaries. The starting salaries of graduates of a given school has far more to do with geography than it does the quality of the school. A “crappy” school in NYC is likely to have a higher average starting salary than a “stellar” school in Nebraska simply because of where the graduates tend to live and the associated costs of living.
Second, PhD programs do have some potential impact on your undergraduate education. Do you have any interest in getting experience in undergraduate research? If so, then having a strong PhD program generally correlates well with strong research opportunities.