I don't think you understand signaling well.
Eliezer managed signaling well enough to get a billionaire to fund him on his project. A billionaire who fund people who drop out of college systematically in projects like his 20 Under 20 program.
Trying to go the traditional route wouldn't fit into the highly effective image that he already signals.
Peter Thiel (the billionaire) has the proven ability to spot talent, which is why he is a billionaire. Eliezer has traits that Thiel values, and this is probably much more important than any signal Eliezer sent.