My son once asked me why so many people go to bootleggers (now and in the past).

My reasons included:
After hour purchases, as booze stores used to have limited hours and were not conveniantly located, especially in remote areas.
For cheaper (and higher octane) illegally produced (or imported)booze.
For smuggled tax free booze (much cheaper)
Some folks were banned from getting booze at liquor stores.
Quanities were in some locations limited and at times booze sales were completely banned (prohibition).
Underaged drinkers
Some bootleggers gave credit, until the pay checque arrived.
Just for the novelty of it.

Years ago, where I grew up, a doctors note was once required to purchase booze, and later it was rationed through booze books, or stamps. Additionally,, there was once a list of people who could not purchase booze, for a variety of reasons. It was commonly referred to as the "the Indian List" (likely called that for a number of reasons, one being a level of social dicrimination).