Because "0.0.8" is artificial name, that you cannot find in the source code. There was pre-release version, with no versioning, then Satoshi introduced versions here and there, and then he released "BitCoin v0.01 ALPHA" as the first official one. Initially, there were only two digits: major version (equal to zero), and minor version (equal to one). The third digit was introduced later, and that's why that version is recognized as "0.1.0". But it was initially just "0.01". And there was no "0.0" version, because there was simply no versioning at all in earlier code (also, Satoshi started counting from one, the first zero was only used to indicate "ALPHA" state, and was later dropped in 22.0 version by Core developers). If you want to confirm that, you can look for example at block header: note it had no version in "November 2008 code". And if you explore that code from 2008, you will notice that there is no "eight version" anywhere in that code. It was simply taken from the year, and made out of thin air by some people.

And if you don't believe me, then open your "0.1.0" version, and read just the first line of "readme.txt".