There's nothing wrong with an empty tavern per se.
People can go to the tavern to storytell if they want to, or stay at the mine and dig if they want to. A PC can use Auction to announce when he is keeping the bar, in hope to attract some miners. He can also bring his drinks directly down to the mine, Facts like those won't change whatever the poll results will be.
What Mythryndel says, and I agree with, is that the place is empty when we pass by. In fact, the entire town is pretty empty. So why come back? And why stay around? To be lively, a place needs passage, not necessarily players camping there.
One way to attract people to the place is to put a NPC merchant customer in the tavern (not interfering with PCs bartenders), and maybe some creatures to hunt in the valleys around. Hunters will then go there to sell their parts or hides, and take a break.
Or just move Grok there once in a while? Or simply some of the Gugrontid NPCs?
Personally, I don't care if the place is empty or not. Maybe it has been busy for the last 4 days, but who knows how long that will last? It looks like the stove makes many players happy though, so maybe wait and see before adding anything else, for it could already be good enough after all.