My current guild has a show every year and it is profitable. Personally I like every two years. I always volunteer to work at the show but I am not on any committees. I also make a little quilt for the silent auction.I have previously served as chairs or officer positions in this or my previous guild and I no longer want to commit to be at every meeting etc. In the last two years some of the 6 smaller guilds have combined with a company and they do a big show together. The guilds have limits on how many quilts each can place in but they each have a boutique booth to sell things and a combined silent auction. The make money on tickets they sell before the show also. I have heard this is working well for them.
I think there are valid points made in previous responses. It is hard sometimes to find a good venue and the costs keep going up to rent them.