Almost certainly will not happen. Any marathon that pays the appearance fee for both Mo and Galen won't have much let over for the other invitees. London for all practical purposes is the debut for the GOAT track distance runner and a non-African WMM winner will command a king's ransom. With that said, if the 2 of them just happen to end up in the same race, I will have to go with Galen, the proven marathoner. Mo's 59:32 half from 2 years ago suggest he is definitely better than his 2:08x, but I don't see Mo being able to run with the ultra elites.