Okay, I am speaking in very broad terms here, but I thought I might give a longer historical view...
I started with miniature wargames and AH boardgames back around 1970 and have kept gaming ever since.
In the pre-rpg days, gamers were male and white, pretty much period. They were also primarily interested in history, meaning almost entirely military with a dash of political and little to no social, and were into minutiae. They were above the curve in intelligence and somewhat below the curve in social abilities. There was a greater interest in science fiction than fantasy amongst those who read genre fiction -- in those days there was a pretty hard "sneer divide" between the two as sci fi was seen as the more "serious" literature, while fantasy was seen as "childish", but both kinds of books tended to be hidden in bookstores in odd corners.
The early days of rpgs brought a slightly different mix to the games. Again the gamers were white (actually pasty pale) and male, but they were also geekier and more interested in fantasy (although there was a strong sub-segment of sci fi fans ... which led to an interest in not only
Traveller, but also psionics in D&D groups). The image of the immature, socially awkward, fat, and bizarre as the standard gamer was pretty standard ... coupled with the notion that the standard gamer was smarter than your average bear. Early conventions had an interesting miasma to them -- bodily hygiene was pretty low.
As gaming has gone one, the average age of gamers has shifted forward. Where in the early days (late 70s and early 80s) most of the gamers were in their teens and very early 20s, now most groups I have seen are further into their 20s and often into their 30s. Myself, I am about to turn 50 and my current gaming group ranges from 25-38. The hygiene issue has gotten better, but still could do with some improvement. The greatest changes I have seen are those in gender and ethnic mix. There are far,
far more (as a percentage) women involved in the hobby than in the early days -- it is uncommon for me to have a game group anymore that does
not have one or more women, where when I went to my first convention back around 1979 there were maybe 4 women gaming
in toto. And now there are many blacks, asians, latinos, and others involved in gaming -- such as my current gaming group where I am the only white person at the table.
Conversely, the "obviously more intelligent" factor has come down a bit -- this is not such a bad thing, but it does change the tenor of the game.
Still, a lot of rpg-players are so focused on their games that they have a hard time seeing beyond their table/board to see how they appear to outsiders. The obsessive talking about their characters and campaigns, the hogging of space in FLGS, and, the lack of care with their trash. I have seen several games stores where comparatively new customers have been driven away by obsessive gamers.