That's a good point. I don't have time to double-check your numbers but I will assume they are correct.
My only rebuttal (if I'm to take an opposing position), would be that different organisms have different clock-cycles, an example would be organic life, hummingbird metabolism versus elephant or whale metabolism. I don't know if their brains are also faster, but since their reaction speeds do seem to be connected to their metabolic rate, it's probably the case.
Considering architecture, the way intelligence is being created through Machine Learning is through cellular units that carry large amounts of information digitally instead of oscillating analog signalling. In fact, I found that when building cellular automata, black-white automatas are elegant in theoretics, but when it comes to what will deliver the most complex/intelligent dynamics on a GPU, it is using each cell/pixel as a complex number, floating point, or vector of such types. The GPU can do so much with single units, so it makes sense to use its full potential.
It's possible that the encoding/signalling of galaxies is similar. Clock speed only has to be as fast as things you _can_ react to. Can a galaxy move fast enough to dodge an asteroid? Likely not.
It'd probably be enlightening to know more about how the brains of larger, slower animals such as elephants or whales operate. Their "clock speeds" might shed some light on what kind of parameter ranges life operates within.
EDIT: one more thing I thought of is that it's very possible that the living stage of the larger structures of our universe is simply young, adolescent in nature. Perhaps we are living at a time when the intelligent behemoths among us, or rather, that we are apart of, are of their first generation. I agree though, it's more unlikely to be seeing the head or tail of a distribution than somewhere in the middle. But we should not rule out young, large intelligences.