It probably never did. Owing to the very limited testing then and even now, we have certainly missed a lot of cases.
That said, when they do end up in the hospital, they usually tend to be seriously ill. But that tells us little about the frequency of such high acuity cases. Still, severe influenza A subtypes are no joke.
One of the other things is the very high fatality rate from H5N1 generally has come, previous to this current strain, from primary cases with very intensive exposure to the avian-adapted strain, which is much more fond of receptors in the lower respiratory tract.
Those types of cases for many infectious diseases (i.e. MERS) are much more lethal than subsequent human-to-human infections.
