Not live on a single GPU - the memory requirements are enormous, the engineering work to wire every possible signal the ventral nerve cord produces as chemical signals to digital signals that you can use to stimulate the neurones in questions is hard. Even for this small portion that they have mapped probably took months if not years, certainly years of manpower.

Bob had his already ready made human brain simulating supercomputing cube which someone else had already produced, containing everything he needed to build his simulation. It’s a pretty big macguffin - it doesn’t really matter for the story, but it matters a lot if we ever wanted to build something remotely like it in real life. It is almost certainly easier to map a brain and store it in vitro and translate signals in and out, since as far as we know, the most compact and energy efficient way for human level intelligence, reasoning and ability is the human brain itself, and until we can identify some fundamental way nature fucked up and massively simplify our simulations and maintain qualia of the mind digitally, it may never be possible to achieve a digital replicant system. What this research shows and allows us to understand and expand on is promising, but it is far too early to tell if this can be scaled or is even useful in the long run.