The timing of this with the larger global conflicts that started in the period seem to me to be totally tied together. My impression is not that of an increase

The timing of this with the larger global conflicts that started in the period seem to me to be totally tied together. My impression is not that of an increase in democracy and anti-jacobianism, but one of increased militarism. I don't know where I heard it, but, 'men's fashion marches with the army'. That's something I've always seen as a truism, and maybe one born from the time period in question. The explanation I heard was that this was due to the inherent value that society places upon men to do the dangerous work of war fighting. So, in peacetime, men whose dress imitates and looks akin to the dress in the military are then seen as more masculine. Crucially, you can't just dress like a solider when out and about unless there is a war on or if you are required to dress as such by being on duty. Stolen valor and all that jazz. You can only imitate. Male fashion is just such a deliciously complex topic, especially since this renunciation, as it's all about the very tiny details and very subtle changes. So very military these things are!