Keeping in mind the rule that 100 psionics will be found in a population of 45,000, the question then arises, where will these psionics be? Given the logic of psionic power, it seems clear that psionics will NOT be randomly distributed through the population. Rather, psionics will become concentrated in powerful and leadership positions, and thus, PCs will be even more likely to encounter them than the "simple percentages" indicate.
Remember, psionics are found only among people with high (16+) INT, WIS, or CHA scores. In other words, these are your natural leaders to begin with. Adding to their natural abilities are their psionic gifts, which they would use to leverage themselves even higher on the social ladder.
Imagine some random person who naturally had the psionic devotion of Invisibility. Do you think that person would stay a field hand their whole life? Of course not! I mean, just imagine the possibilities if you discovered as a young teen that you could go invisible... What sort of adventures you would have, what sort of trouble you would get in...
I am thinking someone with the natural ability of invisibility would gravitate towards espionage, thievery, assassination... Perhaps some would enter the field of law enforcement, and what a detective they would make! Clearly, no one is going to remain an "average citizen" for long with the natural gift of invisibility combined with a high INT/WIS/CHA score.
Just as a thought experiment, what would you do with the natural ability of shrinking size (Reduction)? Or walking on water/feather falling (Body Equilibrium)? Phase shifting (Etherealness)? Levitation? Changing appearance (Shape Alteration)? Teleportation?
Is it just me, or do you get the impression the Thieves and Assassin's Guild would be crawling with these guys???
Or, conversely, they'll be "the Supers", the heroes with superpowers hired by the government to combat these super-powered bad guys. People with Clairaudience or Clairvoyance? Detection of Good/Evil? Object Reading? Sensitivity to Psychic Impressions? These people are tailor made for law enforcement!
And what about Telempathic/Telepathic
Projection? Empathy? Precognition? ESP? Hypnosis? Domination? Or even Mass Domination??? These people are born to rule! You are practically guaranteed to find these powers among the ruling elite, either in the rulers themselves (high CHA) or in their "handlers" (high WIS).
A quick glance at the 1e Monster Manual entry on "Men" confirms this logic. Under each subheading, it states repeatedly, "leader types will have the normal potential for psionics." In other words, it is practically axiomatic: psionics will rise to leadership positions.