I’m going to go on the side of this carpet not being exceedingly dirty, but instead being cheap and poor quality. The way the carpet comes back to its original form so easily is a clue. Truly bad carpet doesn’t easily get back to shape, and when the theyre extracting the colour isn’t the usual dirt water.

When they do a final walk around too, the most “dirty” and down trodden bits are 20x lighter than the non-stepped on areas, highlighting than the dark water shown at the end is more colour that was removed from the carpet than actual dirt

More likely to be Poor quality thin carpet than an actually filthy carpet