Of course the metal can support a person. It's not like one side is floating in thin air. The way this is constructed, both sides of each step are supported and the metal seems thick enough to support quite a bit of weight.
The only thing that bothers me is that forward/backward motion of the steps would put a lot of strain on the connection to the wall or floor. With normal use, that motion is quite limited though.
I'm quite confident the designer of those stairs used the right thickness for the material used, which you can't judge from a picture.
I guess that would also be a legitimate concern, as the steps are rather short. It would look a bit less sleek with longer steps, but making the steps longer while keeping the supports narrow would still look good in my opinion.
Yeah, I am, without sarcasm, super agile and coordinated. I would love to have these steps. It would be fun for me every time. And I'd feel so safe at the top of my tricky stairs. Unfortunately my wife would never. She'd just be trapped downstairs.
I run 6 miles every other day. A local rails-to-trails path near me is exactly 2.5 miles long, so I have to find some way of getting in an extra mile on my runs. The trail ends at a real railroad track, so for a while I tried running a half mile on the track and back, between the rails landing on every other tie as I ran since the distance perfectly matched my stride. This went on for a couple of years until one day I was doing it and actually started thinking "wow, this is pretty amazing that I can do this and not fall". Not five seconds later I tripped and fell, landing both elbows and both knees on tie.
Somehow I was only bruised and didn't break anything, and after ten minutes of groaning I was able to drag myself up and even complete my run. That was my last time running on railroad ties though.
Yeah, never take it for granted. You gotta do it on purpose with your feet every time. Learning to purposely activate intuitive motion is the goal. In a way, they're extraordinarily zen stairs. You have to be right there on the stairs every time.
Except I'm not a man, and I don't have a cave. I'm a woman, and I have a cage. But it has to be accessible to my wife so she can let me out eventually o_o So again, no agility stairs allowed.