By your definition nothing is ever fixable because you can't ever fully remove the possibility that your choices have some unknown effect. A perfect solution never exists so looking for one is idiotic, we can only model the problem with our current knowledge and work on fixing it with that. Compared to other animal life I say we're even doing a good job at it, so far we haven't gone extinct despite being the predominant life form pretty much everywhere. Other animals would've ran into major problems sustaining themselves within two or three generations were they in our position. So unless you have some way to solve our problems that doesn't involve regressing back to the stone age I think the "fix it now, worry about the new ways we broke it later" approach is the only workable solution we have on hand right now.