They’re using their newly acquired license to TTD to hold the better remake hostage, presumably in the hopes that enough people will pay up. You can still play OpenTTD for free if you already have it on your account or download it directly from their website: https://www.openttd.org/downloads/openttd-releases/latest
You can also donate to OpenTTD, as they will receive none of the money you give Atari: https://www.openttd.org/donate
Can someone explain why and how OpenTTD is being forced to do this? I’m out of the loop.
My understanding is - The copyright for the game OpenTTD is based on was held by someone who didn’t care that OpenTTD was distributing game assets as well. This is actually pretty strange in the “indie remake” scene. Usually you have to buy the original game and copy the assets over to the remake.
Now that Atari owns it, they don’t like that.
OpenTTD doesn’t use any assets from TTD, all code, graphics, sounds etc are original. That said, it does aim to replicate TTD closely and has far surpassed that.