that still might be too slow, though, a "week" in the game is 10 days, that's 10 full long rests, if you think of a session as maybe containing one, maybe two long rests, it could take a whiiiiile
we can also make this much faster by rolling on the table Every Day rather than Every Week. More fun: a roll on every long rest. This lowers the expected value of the roll to 31gp a day (the bonus of the roll is determined by how many days between rolls), but it just means they've gotta hustle on those +10 bonuses more.
if they're doing about three heroic or tavern-friendly things per long rest, that has the place paid off in 8-9 long rests, which is much closer to where I'd want it to be.
keep in mind if we assume that our players long rest about every 2 hours, we play about 4 hours a month, that means that the tavern is profitable in about 4 real life human months
just now realizing that this has made the tavern's operating costs 60gp/day rather than 60gp/week, which is much higher: I can fuss around with that to make it more dramatic...