Her music is WAY more polarizing and specific than theirs. Taylor has the pre-teen white girl demographic in a tight grip and no matter what Beyoncé does or releases she'll never have the inter-generational appeal Adele has due to her image and sound.
But I mean she's WAY WAY WAY more acclaimed than they both are so at the end of the day #musicnotthebling
No one can compete with Adele's album sales tho..usually artists that make music like her, sell like that..although there haven't been a seller like that since some time I think..
Because people don't buy her albums in the same quantity. But why does she have to compete with Adele and Taylor Swift? This does not diminishes her talent or her accomplishments if this is what the OP is trying to do.