A good game engine with good tools can save users who want to write that type of game a lot of effort. You shouldn't have to write collision detection algorithms to give the user a sword/gun/magic spell.
Looks like some of the original Monkey Island games were taken off the site and replaced with remakes, much to fans' dismay. I suppose there are other ways of tracking down the originals.
Har, har!
> some of the original Monkey Island games were taken off the site and replaced with remakes
MI and MI2, replaced with a 'Special Edition' which does include 'classic mode'.
Industry is not ready for leasing the assets to the end-users. Yet, I hope.
I think the reason for this is something you haven't considered: OpenTTD is extremely repayable, long-term fans of this game put thousands of hours into it. An old Point & Click adventure? Long-term fans might replay the game a few times every few years, but I don't think those sort of games will ever inspire the amount of invested effort that OpenTTD can.
Or consider Morrowind, closer to a Point & Click in concept (the art and scripting is a big part of the draw), but known to be a huge time sink that people can easily put thousands of hours into. And again, you see a very high level of investment from the community. Lots of total graphics replacement mods, mods that add huge new levels dwarfing the original game, etc.
This is really not true for most 2D games. For something like OpenTDD where the art is mostly functional and replacting it will still give you about the same experience as TDD, sure. For something like a Point & Click adventure? Nah, the art and scripting is the game, you might as well create a completely new game at that point. The distinction really has nothing to do with 2D vs. 3D.