Everything you've said about comfort and complacency is equally if not more true of scarcity though. Scarcity leads directly to short-term thinking because there's no future to plan for or maintain. Erosion of social bonds happens as desperation increases and people turn to grifting and taking advantage of each other. The original quote is a little too tidy, an oversimplification that fails to grasp a complex reality and seems to have its own agenda/bias. Which you presumably agree with or you would have caught it. The truth is that there are varying levels of easy and hard times, and either one can "create" either kind of man. (And I'm ignoring masculinity as an issue; everybody knows whether they're a man or not.)

Or I can reframe it one more way: If good times create weak men, then all the rich people currently running things corruptly and soaking up whatever 90% of the wealth, are weak, and all the discipline and virtue in society are among the rest of us. Cultivate competence, responsibility, purpose and pro-social ambition in the super-rich and you might have something there.