Apple will not pull non-sandboxed apps from the Mac App Store. They have previously communicated that existing apps will be able to stay in the App Store. They

Apple will not pull non-sandboxed apps from the Mac App Store. They have previously communicated that existing apps will be able to stay in the App Store. They won't accept new non-sandboxed apps and they won't accept new, non-sandboxed versions of apps with the notable exception of minor maintenance/bugfix updates. Source: the email Apple sent to all registered Mac developers in February.