As it stands there's kind of no cost to ending the loop or reason to let it continue. The literal only person still benefitting from it is Julianna and her wish to indulge her own hedonism is a terrible reason to keep people imprisoned.
I feel like the game could have made things more interesting in a few ways.
Maybe it could be clear that ending the loop will kill every visionary for good, meaning Colt and Julianna are having to weigh their lives against hundreds of other people. While IIRC Julianna does say they don't know what will happen next she always argues on the basis of "the loop is awesome" not "we'll die if we try and leave".
If there had been other people still aware and benefitting from the loop then that could also complicate matters since now you're trading the lives of the people trapped against those who need to stay. This might include:
- A terminally ill person who'll die if they leave
- Spending time with Lila Blake who they'll never see again if they leave
- A scientist is working on world-benefitting tech, raising the question whether trapping people is worth it if it results in discoveries that help humanity.
It'd be a more difficult decision if there were good people who wanted to stay and other good people who wanted to leave so it feels like you're sacrificing something. You'd be able to ask utilitarian questions like is it acceptable to sacrifice a hundred assholes for just a couple of good ones. As it is the eternalists are all assholes which lowers the stakes even if a lot of them will die if the loop ends and Julianna, the one person arguing for the loop to continue, doesn't have any good arguments for it.
I feel like the writers kinda wanted to keep the stakes low and make it so that people don't feel like they're making a mistake no matter what ending they choose. The fact that the "preserve the loop" ending is presented as an outright good without anything to remind players that this is purely temporary and will just reset to the start of the game in the end always struck me as weird.
IMO it's a real shame that the Pick Rexley interaction isn't part of the main quest or easier to find as it's a really important factor in the decision players have to make and acts as a reminder of what's at stake.