The downsides of putting “TTD” in the name “OpenTTD” is a certain level of vulnerability to the original creator (or a rights inheritor) deciding it’s worth their time to care again someday. I suspect this will do more for the TTD community than it will harm it, though; any modern sale of TTD is targeted precisely at the folks who would take mortal offense at harm to OpenTTD, and $10 (which would have been merely $5 in 2000) is the opposite of egregious after 100% inflation pushed AAA games towards $90 these days. I paid $5 for a used copy of SimTower back then, I would happily pay the same today for TTD resources, so this is all fine.

I get that Atari isn’t perhaps as loved as, say, Bullfrog or Dynamix, but better that companies respect their properties and their fans with an outcome like this, than be another boringly-common community-destroying Nintendo Lawyer Takedown Club.

(It’s also now in line with the various WAD and Descent games over time that used this model, where the engine is maximum rewrite amazing but the game resources require a GOG purchase. The point of rewrites isn’t to deprive the games of revenue!)

It's similar to Valve and Dota2. We all know what it means but officially, it isn't actually DotA and doesn't stand for anything. They will never refer to the game as Defense of the Ancients. Seems to have worked for them.

Worth noting that the Atari of today is a shell corporation that has precisely zero to do with the original.