I would guess that the departure of Kim Deal centered around adding to their recorded output or how revenue was being shared from their never-ending reunion tours.
Deal's departure means that they can find a new bass player, record something, and watch as people illegally download their music. How this is going to make anyone money is a good question to put to whoever thinks this is going to work.
They will probably do something, and it'll happen, and people will continue to express their sense of indifference, and then we'll all realize that this matters to the core fan base of the band and not many people outside of that.
Bands have to find a way to survive, and the only way to do that is to break through and satisfy that small number of people who will still pay money for the music they receive. Without them, the numbers don't add up anymore. To ask "should they go on" is to ignore the existing economic destruction of the careers of people who used to make albums that would sell respectably. The money might be out there, but Pixies are just like everyone else--they have to figure out how to make it work and how to get along and how to deal with the outright theft of their intellectual property that continues.