This person clearly didn't actually step on any of these.

#4 is NOT Lego ABS, it is another Lego plastic and is actually quite "soft" and will bend easily.

#5's clips are really too small to be incredibly painful - you need something more like #2.

And if you really want to suffer you will step on something like the off-brand Hubelino Marble Run pieces: https://www.hubelino.com - they, unlike Lego and Duplo, have extremely sharp edges on the blocks, perfectly molded 90° angles. Almost all Lego and Duplo bricks actually have slightly rounded (rounded rect!) corners.

And walking on a entire floor of bricks won't be that bad, as they will move aside like walking on sharpish gravel. The real pain is when you hit a lone brick on a hard floor.