My larger point with the fail condition isn’t that we should present situations with no solutions, but rather that we really need to start understanding Thrive as a very long, high-investment playthrough. And we need an appropriate fail condition throughout this long playthrough, as otherwise, the game itself will suffer.
So consistency with the Microbe/Multicellular Stage isn’t really the end-all-be-all because we are no longer making decisions on behalf of a single part of the game (this would be a change that affects the entire playthrough anyways). The Microbe and Multicellular Stage in total could last around 4 hours, plus or minus an hour. But the Macroscopic and Aware Stages, being the meat of our unique experience with the largest scope, can easily last 7 hours, plus or minus however many hours. These would be changes that affect all stages anyways. Combining the two together, we see a really long chain of events where the player can make a mistake - unless we make choices inconsequential or dilemmas very easy to manage.
I have made larger points in another thread about why environmental events are fundamentally different between the microscopic and macroscopic stages of the game (Changing Role of the Environment in the Macroscopic Stages). We also have discussion on concepts for future societal stages, where the idea of continuity of a playthrough across different cultures rather than national identities is popping up (Awakening and beyond: Culture). But beyond that – we have changed win conditions in the past, going from the 15 generation requirement, to the current, more organic continuing gameplay. We can do the same with the loss condition.
I also will not fundamentally accept reloading a previous save as the go-to, game recommended remedy. This is not to say that it isn’t a valid tool or that every playthrough should be an iron-man run, but that is a very meta solution to what should be an in-game consequence of choice. We cannot be afraid to let a player’s mistake incorporate itself within the world.
Yes, KSP and other editor games do have reloading a prior save as an option, but they do not rely on it: it’s allowed, not prescribed. And because KSP has a fail condition/remedy that goes beyond re-loading a save, it is comfortable to let players deal with the consequence of their choices.
Saving exists as an option to support the player, but it shouldn’t exist to compensate for an under-developed failure system. We risk creating a game that the only decisions that matter are good decisions, and completely circumvent the result of less-than-optimal, or even bad decisions.
The solution doesn’t have to be switching to a completely different species that currently exists. We can allow the player to essentially load up an ancestor that previously existed and continue as that. The important part is that the player should continue to exist in the world that has been created as a result of their choices instead of essentially reversing time as their primary get-out-of-jail card.