This is a legitimate concern, but customers have to balance the utility against the risk of this happening. If an app works for a few years and then shuts down,

This is a legitimate concern, but customers have to balance the utility against the risk of this happening. If an app works for a few years and then shuts down, do you get enough utility out of those years to offset the inconvenience? Would an offline app even be able to provide the desired utility? Probably not if a key part of the product is social.