I have spent time trying to come up with reasons why--and though I am sure my thoughts and reasons may not be the same as your own--I'd like to share mine and hope you will share yours as well. I don't think there is a "one answer to rule them all" goal here, rather perhaps by sharing our own insights we can better understand-why we play, what about them brings so much enjoyment, why are they still relevant in our own lives--and why do so few other people have much interest in the table based games.
As I have been recovering I hooked up my old Nintendo and in a fit of nostalgia began to explore Hyrule once more in The Legend of Zelda. Having not played it since 1987 I had no specific memory of getting through the game and its dungeons but it all slowly came back upon re-entering Hyrule.
It hit me during play, and I do no claim this to be an original thought by any means, that The Legend of Zelda is just a wonderful hexcrawl. You go across the terrain, you randomly encounter foes, you find some dungeons to uncover unique and powerful artifacts--and eventually amass power and experience to defeat the big baddie. Yet before Zelda, the Ultima's, Wizardry and Bard's tales games certainly had various dungeons and overland "hexploration" as well. Yet the previous games were both more regimented/turn based and the platform/ systems they appeared on where less accessible (PC more adult/expensive) then the NES (cheaper/hooked up to a TV in the family room.) I think because of this delivery difference, most people would be easily able to have heard of Zelda, while Ultima, Wizardy, and Bard's Tale would be far less familiar--if at all.
I tested my own lovely wife and she KNEW Zelda having played it herself as a young girl--but the other 3? I got that look when you ask about trying to find some obscure RPG book you left of reading downstairs, that she kindly put away somewhere but has no idea which specific book with a dragon or sword wielding savage I could possibly be tasking her to remember was shevled.
Second, Zelda has you controlling just one character--Link--the others had you controlling a party of 4 or more differing characters, generating names, all of their stats, picking classes and equipment. With the Legend of Zelda--there is just Link. You start with 3 life and the adventure begins. In fact speaking of equipment below is the TOTAL list of 26 equipment items in the Legend of Zelda:
By comparison, just the arms & Armor list of 1985's Ultima 4 is 22 items on its own.
Yes the style of game is different, the level of detail is different and we can get into further discussions about verisimilitude differences in the games influencing the overall design....but that isn't really my goal or point.
I guess what I am driving at is the Legend of Zelda manages to deliver an extremely memorable and brilliant RPG experience--simply. Zelda is extremely easy to pick up and play as well as one inviting you to get right into exploring and discovering. Not that the Ultima's and wizardry are any less good--just that their design is more "detailed/hard core" and that complication making them appealing to a more narrow/specialized taste.
I am not inferring a "mass market" game is a better game by any means, only that removing barriers to entry can(potentially) increase the number of people both playing and overall enjoying this style of gaming (adventure/rpg).
In the immediate gratification/ on demand App age, is the pen & paper game simply an interesting artifact? Is it the effort to explore/create simpler designs a futile endeavor? If not what are the basic elements necessary to impart a fun experience without over burdening players?
This is where I leave off for now.