I think a better way to say it is that few people were picking McCall and even fewer were picking Rahman. Therefore, few people would be picking fighters of a similar standard (broadly speaking). That is why Lewis was a colossal favourite over Mike Tyson having lost to McCall.
He wasn't a huge favorite over Tyson. Lewis was like -180. And sadly enough, I remember picking Tyson to get him out early.
Lewis never faced a southpaw so impossible to really know. Obviously he had the better career so most people will just knee jerk select him. Both guys had the possibility of taking out Lewis. Lewis did well with sluggers he faced them more often than boxers. So he enough background to be big favorite over Brewster. The sanders that blitzed Wlad could’ve easily did the same to Lewis. It’s hard to prepare for an aggressive southpaw coming at you from new angles. no way to really know. Not much separates Sanders and Brewster from Mccall and Rahman- they are all the same level type fighter