It always kind of amazed me that the game studio that wrote the book on crass movie tie-ins saw unfit to take advantage of Indy's long awaited return to the silver screen in 2008 with an opportunistic video game adaptation.
It kinda makes sense when you consider that Staff of Kings was already committed to (well, until it wasn't) by the time Crystal Skull got greenlit, and at the time the company didn't seem particularly capable of devoting itself to more than one or two internal projects - indeed, the rumor was that "choosing" The Force Unleashed to rally resources behind is what starved out the original Staff of Kings SKUs.
Still, it would seem impossible that a Crystal Skull tie-in was never conceived, and a comment left by a former developer on Kotaku's "How LucasArts Fell Apart" article confirms it:
I worked at an outsourcing company for a LucasArts game on the DS. It was Indiana Jones and the Staff of Kings. Originally it was based off the Crystal Skull movie. Through 6 months on the game, it was clear there was a weird managerial tone going on. Almost any company wants feedback and people to present some creativity in dealing with issues and finding any problems with the games they make. Not them. there was to be ZERO DEVEIATION. Even if we were able to see a bug in the game, IGNORE IT. We were reprimanded when we did. The team became dejected quickly. They tried to submit the game and it failed (obviously). It was at this point the DS game went back into development and was no longer based on the movie and ended up being Staff of Kings because it was too late after the movie came out to be related.
It was a weird experience, that's all I have to say about that.
I didn't play it that far in the story so can't really verify if it was just slapped over the horrible Crystal Skull plot.
Ascovel
...And Crystal Skull was originally Infernal Machine and Infernal Machine was originally Iron Phoenix which in turn was Fate of Atlantis: The Action Game.
Every game in the LEC catalog from 1989 on was just an offshoot of Passport to Adventure!