That's just the file layout again.
If I assume that the binary bits are added for 1 and subtracted for 0, then it would be impossible to get the up and down spikes that we see in Audacity, unless the bits are summed every n samples. But if that's the case, it's hardly bitstream, is it?
...or is the Audacity display a summation of what's actually going on? I haven't tried counting the 5,000,000 samples per second to find out.
Edit: I just took a look and that is what it seems to be doing; One sample in Audacity appears to be something like 50-60 bits?
Further edit: That's at a sample rate of 705600, or about 1/8th of the original. Which means the samples (rightly or wrongly) appear to be measured in bytes.