This whole thread is moral posturing about how unprofessional Twitter/Smyte have been, but if we want to talk about professionalism we should look at ourselves.
If you upload to AWS S3 you put in a fallback to another service? And any other AWS services you use? That's a lot of fall backs. Is the second fallback good enough? Should we add a third? In any practical sense development would grind to a halt. Twitter/Smyte are totally in the wrong for not giving a reasonable notice. I think whoever made this decision should actually be removed from their post and the servers should powered back on again with an apology to all of their clients. If they still want to shut it down later then they should provide a reasonable time frame.