YaTEdiGo: One question a bit off topic, but not totally, why STEAM is selling The Last Crusade and here is not available? Did GOG said something about this? They are maybe improving the DOSBOX emulation or some bugs? Or is some exclusivity with STEAM?
Is a bit weird considering GOG got the rights of the classic Lucasarts/Disney games first...
It's because GOG
didn't get the rights of the classic Lucasarts/Disney games first.
Up until Lucas sold it, Lucasarts had a farcical management structure where the president would be fired almost on a yearly basis. One of those presidents, Darrell Rodriguez, was a big classic lucasarts fan, and it was him who licensed monkey island to telltale to produce the Tales games and commissioned the MI1, MI2 & DOTT special editions. He also allowed a limited number of lucasarts games onto steam, and indy was part of the initial batch:
Indiana Jones and the Fate of Atlantis
Indiana Jones and the Last Crusade
LOOM
The Dig
Star Wars : Battlefront II
Star Wars : Republic Commando
Star Wars : Starfighter
Thrillville : Off the Rails
Lego Indiana Jones : The Original Adventure
Armed and Dangerous
I imagine eventually the entire catalogue would have made it to steam, but as was standard for lucasarts at the time, he was fired. When he was canned, the SE of DOTT was cancelled and the process of bringing the lucasarts catalogue to Steam was ended, but the games that were already there remained.