I know you like to make everything we discuss being exclusively a Disney problem, but this isn't isolated to just the remakes or even Disney. Consumers have access to more content than any time in the history of media, and a lot of it is very forgettable shortly after its been consumed. The average human brain doesn't have the capacity to remember all the content released today let alone what released 5-6 years ago. Disney with the remakes tries to rely on nostalgia to cut through all the noise, but even that is getting drowned out as we can see.
Also as has been pointed out, as Disney has been mostly successful with the remakes other studios are now trying to replicate that with their properties, "How to Train Your Dragon" is Uni's latest attempt to replicate the same thing Disney has done for years. So it ain't going anywhere, because if that works then expect Disney to continue with theirs at least in some capacity.