[bombcar]

You can look at it like this: a light rail line is a promise that transit will serve that area for decades to come.

And so when a light rail line comes through, the areas around the stations begin to develop, and quite rapidly, too. An example can be found here: https://goo.gl/maps/kEkn615bp5nUGVmv6 - that trolley stop was literally in the middle of an empty field when it was built, and there wasn't much around on the nearby roads, either.

A bus line gets added to where people already are, and can disappear as quickly as it came; there's no permanency.