And not just any PhD, a Cambridge PhD, using said Tractatus as the dissertation. Astonishing.
Many professors didn't welcome the novelty, including one of Wittgenstein's examiners, who wrote in his report:
"The Tractatus is a work of genius, but it otherwise satisfies the requirements for a Ph.D."
EDIT: I should have said "British" instead of "European", see comments below.
From the United States, the Ph.D. degree spread to
Canada in 1900, and then to the United Kingdom in 1917.
"It is my personal opinion that Mr. Wittgenstein’s thesis is a work of genius; but, be that as it may, it is certainly well up to the standard required for the Cambridge degree of Doctor of Philosophy’
So, it was not seen as an achievement at all!
I don't get that interpretation from that quote at all. To me, the quote is about contrasting the speaker's subjective view with a more objective "standard" requirement for a PhD degree. It's basically saying: "To me, his work as that of a genius. But YMMV. However, even if you don't want to go quite that far, you'll certainly admit that it's great and fulfills the requirements for a PhD."
Not being the work of a genius does not necessarily mean that it's not an achievement.
Just because the thesis (http://en.wikipedia.org/wiki/Tractatus_Logico-Philosophicus) exceeds the requirements for the degree, does not make the degree insignificant.