one other item:  there's an old joke from LEXX about how a planetary civilisation on the verge of
producing the higgs boson is in its terminal phase, which would explain why humans have never
received visitors nor messages from more advanced species. 

but it's more an allegory for the problem that they may spend so much of their resources on
technical minutiae that the rest of society goes bankrupt and the civilisation collapses as a result,
as in the egyptians, romans, persians et al.  IOW the civilisation can only proceed so far until it's
crushed under its own weight, like a beached whale IMVHO.