No , OpenLocomotion would make Chris Sawyer happy if it was like OpenRCT2. OpenRCT2 requires the original game files to run. That means if OpenLocomotion came out , more people would buy the original Locomotion because they need the files from the original Locomotion to run OpenLocomotion.
From what I see with law suites between rival companies, what happens is protection of ownership and of the brand. Money is nice, but not what it is about, I think.
If you use my graphics for 10 years, and then I change my mind, and try to get my right in court, I will have a hard time explaining why I waited 10 years. That means, if I care about ownership of the graphics, I cannot afford to let you use it.
Similarly, if you publish something close enough to Lomo, and something goes wrong there (eg people find it contains a back-door, or you add porn in the game, or advertising, or ...) that bad image will affect my new mobile game as well, as people don't see the difference. It's a similar enough name too, so all advertising, and careful branding of Transport Tycoon being the #1 game to have, goes down the drain. No way I can make a nice sequel game any more. All this because someone not under my control messes up. Can't let that happen if I care about Transport Tycoon as brand.
So yeah, it's about money in the end, but a franchise is a lot more money than any number of sales you can make with any OpenLomo clone.
From what I see, CS cares deeply about the Transport Tycoon franchise. He even bought all the rights back instead of inventing a new name for it. He is making the 4th game about it, after Transport Tycoon, Transport Tycoon Deluxe, and Locomotion, now the mobile game.
EDIT: To be clear, I don't like the copyright system either, but it's what we have.