Yes, there's been discussion in other entries about when exactly the ideal perished, and whether it would have perished if the aftermath of the war had been handled in a way that created a lasting peace, although as always with a counterfactual it's really impossible to say. Clearly for some people the war itself did kill it: Wilfred Owen wrote his poem decrying "The old Lie: Dulce et decorum est/Pro patria mori" during the war, after all. But on the other hand you've got things like Pat Beauchamp Washington's postwar memoir about how working as an ambulance driver was a jolly lark, including funny stories about learning how to walk again after she lost her leg.

I think that the collapse of classical infantry tactics and the absence of mobile warfare and the stalemate are all parts of the same phenomenon: war had suddenly stopped working the way it had worked for a long time, and it wasn't so much the dirt and danger of it changed the view of war (war had always been dirty and dangerous) but the fact that the infantry (and the high command) were comparatively helpless, which does not feel grand or romantic at all.