I was shocked and smiling to myself when I got a load of this.
If you look under your seat, you should see them, though probably still intact.
What you can't see in the pic is there's a square shape formed by the gray cable the rusty springs are attached to. Then, there's 11 wires going straight across or horizontally in the pic to support the seat from caving in [I think]....but, it didn't feel like I was sitting in a hole, so maybe it just recently happened and hasn't had a chance to cave in.
The passenger seat has them too, but all of them are fine. I ended up "rewiring" it with bailing wire.