Think winter, rain, snow
Babies
Single parents
Not wanting to get dressed
Etc
There is a market but agree not large enough to sustain this much competition
In most of these conditions you can usually plan ahead and use the delivery function of any of the major supermarkets - at half the price and ten times the selection. Their delivery window might be a one-hour slot tomorrow, but for anything but impulse purchases or shopping for the 1%ers that's mighty fine.