Why should it be "closer to dial-up", when similar devices are used to drive fibre-optic connections etc?
A slight exaggeration on my part
But there are major differences- for a fibre the diode output is tightly coupled to the fibre, there's very little loss between sender and receiver (in particular the inverse square law is irrelevant), hopefully no ambient light so not much power required.
With a remote the light is sprayed out over quite a wide angle, inverse square law takes its toll, the level at the receiver has to be high enough not to be swamped by ambient light so a fair amount of power is needed. It's harder to switch high powers than low ones.
There's also multi-path propagation (echoes) to think about- I can often use my remotes pointing directly away from the receiver by bouncing the light off a wall or two. So there can be several metres path length differences, say 10nsec difference in arrival times which could make anything above about 20Mbps distinctly iffy.
The same applies with fibre- if you want the maximum possible speed and to hell with the expense you use single-mode low-dispersion fibre with a highly coherent laser, not multi-mode with a diode. The multi-mode effectively means multi-path, and higher dispersion means the light velocity varies with frequency, thus different "colours" sent at the same instant are separated by the time they get to the receiver.