That's like saying blue bubblegum and pink bubblegum make for a diverse range of foods. I guess maybe that seems like the case, given we've all mostly been eating bubblegum for some time.

There are far more similarities in these songs that have a greater impact:

* Very similar tempo (approx 120 bpm)

* Very similar keys (Eb Major vs Bb Major)

* Very similar dynamics (crushed and loud)

* Very similar ultra-present vocal processing

* Very similar light syncopation (Katy Perry's synth chords vs Kesha's chopped vocals)

(edit: formatting)