no other inscriptions are known in the great pyramid ?
a needed major discovery made just in time for justification and further funding ?
It's worth pointing out that there is not just a single inscription in the pyramid.
Page 275 from Mycerinus: The Temples of the Third Pyramid at Giza (available as a PDF from the linked page) includes a list of some of them. Some, like The gang, The Horus Mededuw-is-the-purifier-of-the-two-lands (Mededuw being one of Khufu's names) were only found once, but The gang, The-white-crown-of Khnumkhuwfuw-is-powerful is known from over 10 inscriptions.
Here is a plate from a book showing the graffiti in a chamber in the great pyramid. Other plates in that book show further inscriptions.