Oh, good lord. This is happening now. Jean sandal boots are happening everyone. Perhaps their tagline can explain it for you:
What do you get when you combine the silhouettes of a thong sandal and boot? A divine new edgy hybrid shoe! These thong sandal boots are gladiator-esque with a cylinder of beige denim fabric starting at the back of the heel, wrapping around your legs, and ending just around your mid-calf region. These Roman-inspired sandals feature a 0.25-inch heel and functional back zippers for easy on-and-off wear. Would you dare to wear these super fashion-forward sandal booties?
Ah, wait, that did not actually explain anything to me. You know, sometimes things have not been tried not because people are not brave enough to try them, but simply because they are a very, very bad idea.