Earlier quoted context omitted.
Even if each dataset is biased, I’m not still not sure how you derived logarithmic growth from the general notion of bias in data. For instance, assuming the data is biased, perhaps it is biased in the other direction and contains more common patterns compared to the underlying distribution.
There is a lot to this subject, it might be easier if you took a look at https://martinapugliese.github.io/data/heaps-law-languages/ . Note that when plotting corpus size vs unique words, the log plot is expected to be linear.
I think you argument is that this means smaller datasets are ok because they contain "most" of what the larger datasets contains. But I think this data-power-rule implies the opposite. ML models can often get to 80-90% accuracy on some task. Unfortunately, these models often aren't that useful because that missing 10% of accuracy matters a lot to users. So what this data-power-rule implies is that, in order to get the last 10% of gains, you need 10x the amount of data.