IME, local breweries are open Thursday, Friday, Saturday, and Sunday. They are like bars, but only sell their own beers along with wines/ciders of local origin.
Yebbut, a brewery would have another source of income from selling their product tho other outlets. Could you keep your store open three or four days a week and support say three full time employees?
It’s complicated and would vary by state, as laws vary widely. Smaller breweries actually prefer to not sell kegs to area bars. They cannot get a decent markup from what I’ve heard and they want to encourage draft consumption on-site. Some niche breweries have people waiting in line overnight before a new beer release. You cannot get that kind of response if your beer is available in bars.
The brewer/owner often works seven days a week. I’ve hung out as a volunteer, on loading sacks of grain and the like. Small breweries that do some canning often rely on volunteer labor, sending a case home with you as thanks. Their bartenders are part-time, working primarily for tips.