Why are sci-fi scenarios so thin on the ground?

[aramis erak]

And Vance was the only one who used this magic system

wrong. Vancian magic as portrayed in D&D isn't a tight match to Vance's work.
Vancian Magic a la D&D is used by Bill Willingham in Ironwood. (Naughty, but well written, comic)
A few other authors have made use of it as well.

 

[Nobby-W]

That reminds me.

Once upon a time I had a party acquire a terminator robot in a game. However, they didn't have the supervisor password to reconfigure it. As it turned out It was configured with the 'Sales' personality so every time it completed a mission it would launch into an upbeat sales pitch. It also had a glitch in its vocal system so it talked like Max Headroom.

They would order it to clear a building (for example). Sounds of gunfire, screaming and explosions would ensue, then a voice would start up " . . . And that concludes our demonstration-stration. HiHiHi there! I am the new T1000 Ter-Ter-Terminator from Arnoid cybernetics cybernetics . . . "

 

[Bohandas]

wrong. Vancian magic as portrayed in D&D isn't a tight match to Vance's work.
Vancian Magic a la D&D is used by Bill Willingham in Ironwood. (Naughty, but well written, comic)
A few other authors have made use of it as well.

But the vast majority don't, the vast majority use systems that are fundamentally different from vancian magic in a way far larger than the ways they differ from each other.

EDIT:
Or actually, you could say there's three basic ways, out of which vancian is by far the least popular.

The most common is the say the words/make the gesture/wave the wand and something happens that we see in Harry Potter, Sabrina the Teenaged Witch, The Owl House, Dr.Strange, The Evil Dead, Child's Play, etc.

The second is the big elaborate rituals with lots of props type of magic seen in works such as Macbeth

And last and least is Vancian style magic