First, since the bombings in Boston 2013, the various marathons have made less money off of their races because of the security costs. The various changes over the past couple of years have resulted in a savings of $100,000 for each race. For NYRR, that is probably negligible, but for the BAA, or Chicago, that's huge toward their bottom line.
Second, the charity component is, to me, a little unnecessary. How much fundraising does each race have to do? $150 Million total amongst the races, well, let's just add in 280,000 more? Really? But here's the problem - that additional money will garner more media and public attention than any of the runners. Let's face it. 99% of the long distance runners in contention for the AMM Prize money are unknown foreigners, or American runners who train behind closed doors 45 weeks out of the year. Outside of people who read these boards, no one cares to follow their training/racing/etc... outside of marathon week.
This second problem has been an ongoing one for long distance racing and even the internet and social media has barely been able to crack it.
It stinks that prize money is getting reduced once again, but, these races are businesses. There needs to be a return on the investment and with most of these athletes - there is absolutely none. Watching ESPN flail around to find a public interest story during the NYC Marathon is comical. NBC during the Olympics Marathon....it goes on from there. None of these runners are interesting, exciting, entertaining, or showmen.