Here's my pet peeve about big marathons... first, here's some data from our local marathon.
Revenue to Competitor: >$3 million
Revenue to charities: millions
Increased revenue to local businesses: Est. >$20-$30 million (couldn't find source so I'm remembering this.)
Of this $3M to Competitor Group, millions to charities, and $20M to local commerce, how much comes back to the local running community? The answer is not much at all.
It should be at least $100,000/year. The construction company that built one of our bike paths told me that they could build an 8-mile dirt running path for about $300,000... not a single track trail, but an honest to goodness 10 foot wide, hard packed dirt trail.
This is what I'd prefer to see, but it's going to take local runners and running clubs to demand it.