[numpad0]

I suspect the excuse is more like "it'll be nice if we had to warranty replace fewer water damaged phones" than it being a major selling point. Some places rain a lot, and not everyone sort trousers and purses by rain resistance.

[dns_snek]

Did any manufacturer ever replace water-damaged devices under warranty if they weren't advertised as being water resistant?

I've literally never heard of that happening, and even those that are advertised as water-resistant usually don't cover water damage under warranty.