PD, yes there have been many closings of galleries, and many have gone into private dealership. Businesses change, the internet has affected many galleries. One of the galleries that I'm with claims 30 percent of their sales are from online, and this is a gallery that's been around for 30 years.
If one just looked at the profit/loss statement for GM and Ford they'd think that cars were gong to cease production sometime soon. Yet Toyota is expanding. Did anyone think 30 years ago that GM and Ford would be in the shape they're in now. Some businesses grow with economic changes, others perish. The internet has changed nearly all the marketplaces. More and more purchases are done on the internet, eventually some brick and mortar stores will close due to high overhead and internet competition. Some malls will have a hard time filling vacant stores, and if the mall wants to survive they may have to lower rents to help stores compete better with the internet. An economy adapts. Art will still get sold, granted it's a huge luxury, and nowadays people can easily print their own images to hang on their walls, but there will still be a market. Office buildings, hotels, luxury homes, they all use/buy art. The sky is not falling, it's just getting rearranged.