Perhaps the brain could do something similar.
However, there are anecdotes of rare people that subsist on "low pause" sleeping. Allegedly, Thomas Edison had a 24 word day and frequently cat-napped. Contrast that with Einstein who allegedly slept 10 hrs a night.
For modern garbage collection systems (e.g. the JVM), there is no single setting that is best (or even acceptable) for all applications. The same is probably true for sleep patterns.
Evolution does not consider every possibility. And when it does consider one, it doesn't necessary "implement" it well.
(Or would that just render us faster, but much less flexible and adaptable?)
We could change the source, but it might take several hundred million years to finish compiling your new biosphere. And in the meantime the old biosphere might well eat it for lunch. Literally!
I'm glad I did solely because I know that if I hadn't I'd be wondering about both the 28-hour day and polyphasic sleep until I tried it, and I'd probably have more at stake if I tried it later.
It was not good. I tried it in the middle of working on my PhD. I could still write code, but the quality dipped a little. My theory work stopped - the whole abstract complex thought part of my brain shut off - and it took me a while to notice. There was some digestive confusion for a while as well - the body is a pretty complex thing, and it turns out that (at least mine) really likes it's cycles.
I made it through a week and a half - at least I think it was - it really throws your idea of what a day is. The abstract complex thought bit took a while to come back. It took about a month and a half to recover properly. Would not try again.
What, exactly, has it prohibited?
Memory in humans and other animals may so different from that of fruit flies that drawing such a general conclusion as "Sleep is Garbage Collection." may not be valid.
So smarter people need less sleep?
Is the converse true?
The above analogy leads more naturally to the first conclusion. Give a smart person a cognitive task to perform, and gradually deprive him of sleep; eventually, his performance will be reduced to the level of the average person.
It's less clear how the second conclusion would hold -- that smart people are incrementally affected less by sleep loss than average people. In other words, a priori, I don't think there's much reason to believe that a smart person would be impaired less by losing an hour of sleep than an average person would.
Deriving the second conclusion needs a lot more data. Assuming there is no analog for swapping to disk, the biggest missing piece is the rate of GC. Is it the same for everyone? Additionally, is a given person's GC rate constant? When I go without sleep for two days, I usually need more sleep than when I missed sleeping for just a day. Does this mean there is more memory to reclaim? Or that my GC rate has been impaired? Or both?
More interestingly, how do 'brain-building' foods and activities affect sleep requirements?
Depending on how intensely I exercise, I need more sleep as it's repairing itself, so I think the answer to your questions is either 'probably not' or 'it depends'.
I know that in addition to all this, that apparently sleep also moves information in to your long term memory, and that in certain trades (military comes to mind), that after intense training excercises, it is encouraged if not enforced to get a 'good night's sleep' instead of 'getting stuck into the beers after a hard day's work' in order to properly 'store' what was learnt during the day.
So, if you want to remember stuff, get good a good night's sleep!