I mean, water is also aggressively hostile. We're just really well adapted to it. Even pure water will turn metal into rust unless you're using special alloys.

I mean, water is also aggressively hostile. We're just really well adapted to it. Even pure water will turn metal into rust unless you're using special alloys. Salt water is so bad that even alloys won't save you, you have to depend on sacrificial anodes and exotic surface coatings. Steam takes everything bad about water and jams the fast-forward button until the tape catches fire. There's a reason the first hundred years of steam power is basically just a timeline of scientific metallurgy and gasket technology.