The 1GB was explicitly referred to as your ROM. Sussman does not talk about the streaming data that hits you at run time.
meh... He referred to the 1GB a couple of times and I didn't hear he talk about how humans are much more complicated. Also [as an atheist], my point is not to argue against Sussman, but is to point out that calculating the storage requirements of a human is complicated. Putting aside all the guts, walking, eating, etc, we store an immense amount of information. What is incredible is that 1GB is what is required to specify the creation and evolution of the data structure necessary to become adult (and to die).
The 1GB for a human thing, whether or not it's off by a factor of 10, is the cost to build an infant and dismisses the real complexity of a human. The cost to build a high functioning adult is vastly higher. I don't know what it would cost to build me now (complete with screwed up kidney!), but I'm sure that it's quite a bit higher than 1GB: I've learned English, Spanish, love (or so my wife would say), loveV2 (or so my kids would say), basically every computer language, how to catch a football, how to WALK, how to have sex, how to have a conversation over cocktails, etc.
The magic of computers is that once N programs have run through the process of learning to do something, we can clone it. Getting to "how to speak English" is going to be hard; building 1e9 machines to do it will be relatively easy.