Well let me give you the reason as to why they are not, assuming you aren't trolling. Uber isn't really meant to be a balanced tier, it is meant to a ban list for OU. That means that Ubers are pokemon that are either uncounterable or overcentralizing in the OU metagame and thus not allowed there. If you are calling for them to be moved there to get them out of the OU metagame, then your argument is entirely flawed. Because Ubers is not meant to be a balanced tier, how well a pokemon does in ubers is not considered when deciding what tier a pokemon is placed in. That said, yes they do very well in ubers but not because they are too powerful for OU, but because it is a different environment. For example, about half the tier is weak to dark/bug attacks and many pokes are more specially defensive rather than physically. That means a powerful pursuit from scizor is a lot more threatening there than it is in OU.