Interesting subject, especially for gamers that have been playing those types of computer games for the past ten plus years.
I would be curious as to what kind of sources you find.
Some of my memory of adventure games support your arguments. In the 90's, I was playing a lot of Sierra adventure games like the
King's Quest series, the
Space Quest series and
Leisure Suite Larry.
In fact, my first experience with animated graphic adventure games was Leisure Suit Larry I, in the Land of the Lounge Lizards. I played it on my friends Mac classic, though I don't think it was called
classic back then
Another favorite of mine was
Rex Nebular and the Cosmic Gender Bender.
I miss those kind of games.
The Role playing games I remember, however, did not have a humourous element. The SSI Dungens and Dragon games like
Eye of the Beholder and
Gateway to the Savage Frontier did not seem to have much of any humorous element. Those were the only RPGs I played at the time, though.
The one thing I think about all the time when I think back on my gaming in the 90's is that there were a plethora of flight simulators. Pretty much if there was a military aircraft, there was a computer simulation for it. I was a big fan back then. I had all the Sierra Dynamix games,
Aces of the Pacific,
Aces Over Europe,
A-10 Tank Killer and Red Baron, the first one which does not seem to have a website. I also had a lot of Microprose simulations (Microprose also was the distributor of Rex Nebular) which I would play for hours on end. I remember on new years eve in 1994, I wouldn't go out but stayed home and played B-17 Flying Fortress with the intent of being over some city in Germany, dropping bombs at the stroke of midnight. That was a great way to ring in the new year
Back to your thesis,
I wonder if the limited graphic abilities of computers back then led to cartoon like images which lent themselves to humorous story lines? It certainly seems that now the trend is toward realistic graphics and realistic scenarios.