They do that so they can have theire fans beceause if they stop they know the fans will go away to but littlemonster will never forget gaga SO KEEP EATING NUTELLA !!! Yeaaaah
Gaga works harder than any of them. Most pop is manufactured, Gaga's music is art which is why it turns out so good. Bands who perform live (not pop singers) always take longer than a year between albums. Give it time.
Lana has an unlimited amount of recorded songs (they're not new), Nicki Minaj just drops a lot of singles and Rihanna's management like to make the most money they can, hence she has a new album every year. Gaga takes her time. The result? We get the best music