The following is purely guesswork on my part about Lot's Wife (what was her name?)...
A lot (sic) of what is in the Old Testament Bible is allegorical, just as the parables of Jesus were often allegorical. We still talk about people being "pillars of the establishment". Could a "pillar of salt" in Hebrew times have been a figure of speech, or even a derogatory allegorical term, for someone whose previous good name and character had been lost?
A bit like having "feet of clay"? What had previously been viewed as solid was now viewed as something that could crumble or be washed away.
Lot's wife turned back, not literally while walking away from the town, but figuratively, as someone who went back to the old ways that were now deemed unacceptable. She had been seen as a righteous spouse of a righteous Lot, but then joined the "losing side". She had cast her lot the wrong way.