Google Drive is being monetized - that's the difference. Neither Reader, nor Wave, nor Finance nor a dozen other Google products were/are monetized, so they're the first to go when managements decides so.
If Drive is used by paid users, I think it won't go away anytime soon, just like Google Cloud or Gmail.
If Drive is used by paid users, I think it won't go away anytime soon, just like Google Cloud or Gmail.