Up here in my country , Selling Samsung devices gives these sale guys some commission , So they always try to push a galaxy.
They will be like "If u buy an android device , we will load it with some apps , media and stuff" , "For WP , we won't load anything , you will just get the phone"
(A "Common Man" will be like "oh with android i get free stuff while WP i won't get any , so android device seems better" and also every one says "WP doesn't have good store for apps and games" , This kind of negativity pushes away people)
And also if u face a problem with iPhone or Samsung , since all your friends have either of those , you can easily get help but for WP its hard , only way is to go to store or hunt in the forums.This is another factor.
These people don't want the "risk" , they want to get what everybody has (just like "everyone who got iphones and galaxies and are happy with them , why take risk with WP ? , I will also buy one of them")