It got me to remember one of his appropriately timed quotes he wrote in Gurps Time Travel, one of my favourite Gurps sourcebooks as it dealt with Inter-dimensional travel to parallel universes within the multi-verse. A favourite sci-fi genre of mine.
Gurps Time Travel came out in 1991 just as my friends and I did about 10 years of RPGing. My friend Craig, Jim and I were the last ones RPGing at that time from our large group, but only intermittently.
Why would he put this in the middle of an RPG book that dealt with dimensional travel? Yes, it's true that every RPG player eventually gives up his dice, character sheets, and calls it quits. You don't want to be that pug who's had one too many adventures, etc, or still play once you realize the campaign has "jumped the shark." Everything has its place and time and you eventually have to let it go.
I think though, that this existential role playing question he posed in a RPG sourcebook dealing with interdimensional travel speaks to RPG campaigns in general. I think it touches upon the upper limits in a gameverse. Eventually, the gameverse, if RPGed long enough, is not enough and you have to expand outward to other gameverses. I have a pet theory that the manic logic evolution of all RPG campaigns - no matter the setting (espionage, fantasy, space opera, etc) - is interdimensional travel.
You eventually end up doing it if you're the GM and the campaign is long enough. You will get there faster the more RPGing is done, and the more experience points the players rack up. The GM will have a siren song in his head to bring in elements of other settings he loves just to spice things up, "reward" the players with goodies from that setting (e.g. give a Star Trek character a lightsaber), to either start "fresh" with PCs you love and/or to get the experienced players off-balance as a fish-out-of-water feeling.
The disadvantage though is it could easily be a jump-the-shark moment for players, especially if they don't like it. It could also be a signalling or projection from the GM that the campaign has matured now and is in the wrapping up/ consolidation phase.
Our RPG group was groping toward interdimensionality in our campaigns as early as 1985 when my friend Jim GMed a Star Wars-Star Trek crossover in our FASA Starfleet campaign. I still have his GM notes from that adventure.
1985 Star Wars stats converted to FASA Star Trek:
I also did a one shot adventure with Jim's Star Fleet character to another dimension where Khan won the Eugenics Wars in 1999.
I expanded even further when I had my friend Craig's FASA Star Trek merchant crew encounter DC Comic's The Silver Twist device, and sent them once in a while (at first) to other dimensions, and then full time by 1988-9 for about a year in the Star Wars universe to merge with my friend Jim's WEG Star Wars I was GMing.
When the Twist was first introduced to Craig et al, I even quoted the exact words: No one knows who built the Silver Twist or why. Like the above, Craig's PC and crew had a falling sensation every time. The Twist was even used when Craig;s PC left the Star Wars campaign, as I used it to impart some Force sensitivity on Jim's minor Jedi Knight Character.
That, ladies and gentlement, is RPG unification, when all RPG campaigns are part of the multi-verse, or one giant Gameverse. There is only 1 RPG campaign, a multi-universe, with the illusion of having separate individual gameverses (D&D, Star Wars, etc). They can all be merged as one as they are only one.
It is the manic logical evolution to all long running RPG campaigns and is no surprise to be the backbone idea of Gurps 4th edition, as they placed their dimensional hopping sourcebook, Gurps Infinite Worlds, as the main jumping off book for all their other RPG books (from Magic to Space and more).
At the very least, there is something post-modernist about it.
I continued on when Jim and I about 10 years ago did a PBeM campaign that was out of Gurps Time Travel (though we used WEG's D6 rules for PBeM simplicity): a Dimensional Patrol campaign. Jim's characters patrolled the alternate Earths righting wrongs and all that.
My opening sentence in the very first Dimensional Patrol RPG campaign email:
"Not only does God play dice with the Universe, but all six sides come up."
- Bathroom Graffiti at Dimensional Patrol HQ
I discuss my inter-dimensional patrol alternate Earth RPG campaign by PBeM in a bit more detail here.