Why don't they just increase the size of the race? I've never understood the reason for staying around 30k people when the other WMM are so much bigger:
Chicago 2017: 44,508 Finishers
Boston 2017: 30,074 Started
NYC 2017: 50,641 Finishers
London 2017: 39,487 finishers
Tokyo 2017: 35,911 Started
Berlin 2018: 44,389 Started
Get your act together Boston - If you had a standard then stick to it. Makes no sense.