It's not a "fallacy", the problem is real. Check your mental model with reality. Disregard the "if" that your mental model relies on ("if enough people did it i

It's not a "fallacy", the problem is real. Check your mental model with reality. Disregard the "if" that your mental model relies on ("if enough people did it it would work") and look at what actually happens, and do so separately for different issues, because they all have different contexts and complexities. If those "if"s that your argument depends on never materialize in the real world then the model you use is useless. "Possible" vs. "likely".