Give time for WA to grow on radio. Some radio stations are still spinning POM like crazy

, so most stations probably haven't switched over to playing WA yet. Plus, her airplay is growing on Z100, one of the largest pop stations in the US.
Carly has already peaked on pop and will start to progressively lose AI on that format, whereas Katy's will progressively grow. It's safe to say that CMM will spend at least 1-2 more weeks at the top of the Hot 100; but around that time, hopefully, WA's airplay will be much larger, and the OnDemand streams will grow even more.