Over the weekend, fans of Ubisoft games underwent a minor panic as a rumor spread that Ubisoft might be spontaneously deleting inactive Ubisoft accounts, permanently destroying digital game libraries if users didn't log on often enough. However, Ubisoft has now clarified that users' digital game libraries are safe.
Any service out there has the ability to delete your account whether that ability is outlined in some terms somewhere or not.
If you are truly afraid that a company will delete your account randomly, then I suggest only using services you have complete control over.