I've seen it pointed out that it's an odd choice to use the most well-known example of parallel work in the world as an icon of non-parallelizable work.

Population size responds to circumstances almost immediately because birth is so well parallelized. You can have any number of women produce one baby each all in the same 40-week period. If you put any significant number of women on the problem, you'll get noticeably more than one baby each. And you can increase the litter size pretty dramatically beyond that -- how many months did it take Octomom to produce one baby?

The way to do it is "3 people making a baby, 3 people building a nursery, 3 people promoting the baby shower". Not all companies can do this, or are managed well enough to pull it off, but it's not an insane thing to try once you've already decided to get on the VC gravy train.