One idea for ‘where is the real limit’ is ‘first principles’, meaning the phenomenon studied by natural sciences.
For example: according to the patterns (we sometimes call laws) in physics, biochemistry, and agroecology, is it feasible to grow food in monocultures that rely on external inputs and petroleum products? Not for the long haul, not at all. Yet we do it, and further, we rely on economic systems (e.g. multinational corporations, global prioritization of financial profits) that make it difficult to do the opposite! (Opposite being, for example, ‘restoration agriculture’ or cultivating highly productive, highly diverse agro-ecosystems that mimic natural ecosystems in structure and function over time and space.)
Economics (as in, how we manage our ‘households’ at different scale) and political will is often where we stray from first principles (for some time). We can economically incentivize all we want, we can make all the political noise we want, but eventually we get constrained by higher and broader drivers. “The buck stops”…here and now, in accordance with natural trends and constraints.
We’ve pushed well out of bounds, so it will take some change to get back ‘within our limits’. A framework to work on is ‘relinquishment, resilience, and restoration’ a la deep adaptation (https://jembendell.com/2019/05/15/deep-adaptation-versions/). May peace be upon you.