It might be interesting to invite Michael Andre-Driussi into this discussion, since he did such a good job on other aspects of the literary origins of
Traveller. He has written for SJ Games, by the way (specifically
GURPS New Sun), so he may even have a SJ Games forum account already.
Additionally, there are some
Traveller pioneers who could offer their own histories if they were asked at the right time -- for example, if Marc Miller turned up at a game convention Q&A. Sadly, the most accessible Traveller pioneer is gone. Loren probably could have told us a lot if we had asked him while he was alive; he probably could have written a great JTAS article about it too.
One possible literary explanation for
Traveller psionics, particularly suppression, is inversion of literary examples, rather than copying. There are a fair number of examples of psionic aristocracy -- notably the Darkover series, which dates back to the 1950s -- and it's not ridiculous to imagine designers looking at a source and saying, "Let's do the opposite of this."