Yeah, I wouldn't want my panels hanging like that.
While steel can rust, especially if you are near the ocean, properly coated it will last a long time. I built the rack for my 4.4kW of panels mounted on a shipping container from steel. I built it all to fit, took it apart and had it powder coated. It still looks the same as it did several years later. And the powder coating was cheap. The local shop will give you a deal if it is just a few pieces and you don't care what color it is. In my case I wanted a particular color so I paid a little more.
Jonathan