@Autumnal Wanderer
That actually is a thing, here in Germany. It's rare, but some of the bigger cities have medieval taverns/inns. Complete with special events like feasts including live music, 'roleplaying dinners', days with discount for people in medieval clothing, regulars' tables of PnP RPers, LARPers, HEMA fighters, etc (though all of them are there to drink, not to play or fight

), lots of meat and different kinds of mead.
It certainly depends on your location and the overall interest in medieval times, roleplaying and general nerddom, but don't just write that idea off. It's completely within the realm of the possible, and judging by the places I know, they even perform very well.
I suggest you first figure out how much of a scene there is, where you are. Usually there are a lot of one-time-visitors who are just curious, but such an establishment is founded on a strong community of regulars, I think. Find out about LARP and HEMA groups, whether there are any Renaissance Fairs nearby and how well they fare, groups of people who are really passionate about them and camp there with medieval gear, etc etc. A thriving metal and gothic scene are a plus, too.