The 21st Amendment gives states the power to regulate the sale of alcohol within their borders. Some states decided to assume control of all alcohol sales (they’re known today as control states). Most of those that didn’t adopted laws mandating a state-based middleman between alcohol producers (brewers, distillers, wineries) and retailers (restaurants, grocery stores, liquor stores). There are some exceptions, but generally in three-tier states no one is allowed to buy directly from a producer. Everything must go through a distributor.
For decades wholesalers have quietly added 18-25 percent to every bottle of beer, glass of wine, and shot of liquor you pour down your gullet. And there's been little resistance to them, for a few reasons. First, wholesalers don’t interact with consumers. They take their markup between producer and retailer, out of the sight of the people whose money they’re ultimately taking. Second, they’re rather powerful. Alcohol wholesaling is a lucrative, concentrated industry that reaps enormous benefits from policies whose costs are spread out across the general public.
It would be much better to cut out the middlemen and put a 18-25% tax on alcohol and directly use it to fund state government.