There is no progress, and with them not to progress is to fall back and into the Abyss.

In their own lives they may only start to fall, leaving the fall to be completed by their children and their children's children.

Man always gets less than he demands from life; and so little do they demand, that the less than little they get cannot save them.
At the best, city life is an unnatural life for the human; but the city life of London is so utterly unnatural that the average workman or workwoman cannot stand it.

Mind and body are sapped by the undermining influences ceaselessly at work.

Moral and physical stamina are broken, and the good workman, fresh from the soil, becomes in the first city generation a poor workman; and by the second city generation, devoid of push and go and initiative, and actually unable physically to perform the labour his father did, he is well on the way to the shambles at the bottom of the Abyss.
If nothing else, the air he breathes, and from which he never escapes, is sufficient to weaken him mentally and physically, so that he becomes unable to compete with the fresh virile life from the country hastening on to London Town to destroy and be destroyed.
Leaving out the disease germs that fill the air of the East End, consider but the one item of smoke.