Perhaps an institution may go for the iPad as it is harder to bypass the security and root/jailbreak and install apps (APKs) from a PC.

On the other if you are like me and prefer to read from a 10" or a 12.4" (Samsung) tablet, for which I don't mind the 'no updates', as I use it only as a reader that is always on Airplane mode and never connects to the internet. But I have no idea how many people go to that extreme (use a tablet only for reading and zero online connection).