Only ten people were pure enough to be saved
Ten? How did you come up with that? Better go back and re-read the account in Genesis 19. God would have spared the city if only 10 were found, which they could not find even 10 righteous people.
It was only Lot, his wife, and Lot's 2 daughters. However Lot's wife looked back and was turned into a pillar of salt, so it ended up being only Lot & his 2 daughters = 3, not 10.
Actually none of them were "pure" enough to be saved. Lot was willing to turn over his two virgin daughters to be raped by the angry homo mob surrounding his house, and the angels had to yank Lot back into his house. Then the angels had to physically pull Lot out of the city. Later while dwelling in a cave in Zoar, both of Lot's daughters got Lot drunk and then commited incest with him and each daughter became pregnant. Thus from these offspring, two more nations were formed (Moab & Ammon) which hated & tormented Israel hundreds of years later after coming out of Egypt to the Promised Land.
My mistake.
And now, today, Moab is the only town in Utah on the Colorado river.
(And it’s been bought up and overrun with fleeing Californians!)