She could
NEVER. I like Katy but...
Katy has built her career around an image of her being 'innocent yet sexual' (always talking about her love for Jesus, fruit and ******* while she parades around in cupcake bikinis) Did I say *******? I meant cats.
Britney started her career using a similar image of 'innocent yet sexual' but that was ok because
1) Britney was a teenager at the time, not a woman in her twenties
2) She grew out of the innocence and established herself as a 'sexy pop star'
Also Britney was/is a pop culture icon and Katy... Is not really :-/
Katy is currently part of the 'hot **** pop starlets' group (along with Rihanna, Gaga and even Britney) but I don't think she has made a big enough mark on the industry to be considered for the 'trinity'
