Actually I remember Kareena being praised after ages for that song in 2015 (including by me) - she looked her best in YEARS. And I also remember PC being thrashed - people said she would never make it. They also said she would be outshined by Anushka and Deepika in those films (including me) but we were all so wrong.
I wouldn't say PC's career is going nowhere - in fact her popularity has increased so much since 2015, and she's still on a high.
Whereas Kareena is experiencing the best phase of her career since roughly 2010. She's doing SO well right now - looking amazing, and everyone is saying she's the best thing about Good Newwz - and it looks like being a big hit.
We don't need to bring one down to praise the other. They are both actually genuinely doing very very well. It's all good.