Are the Prius prone to rust at the lower front edge of the front doors?

Both front doors on my 2017 are showing rust at their lower front edges. On the driver door, it even started to show from the outside. Is this common for the Prius to rust there? I took out the rubber grommet nearest to the edge, blasted some air and then applied Fluid Film in and out, hoping to slow down its progression.

I wanted to clean it better from within the door through the speaker opening but that speaker is riveted in place! What? Why do that! Anyway, that's the best way I found. Any tips to slowdown its progression even further?

Thanks

 

no to what? Prone to rust there or ways to slow down progression?

 

Ok, thanks.