Why don’t the pubs ask the brewery for free beer?
If the bands have volunteered to help, then that’s fine as a fundraiser for a treasured venue. I’ve seen that and done it.
My band plays in a friends pub each month at a third of our normal fee as we love the guy, love the gig and it helps put an amazing venue. Win. Win. Win.
But if the economics of running the place don’t stack up, it’s just a matter of time before it all ends.