"Glory" is closely related to "reputation". For a soldier (as for many other professionals) his reputation is important. Musicians like to be clapped - and especially they like to be admired by other musicians. And so on. It's no different for a soldier -
Except, of course, that a musician or a surgeon doing his duty is not commonly at personal risk. A soldier can come up against a situation where he can either turn tail and save his life, but lose his reputation, or bravely continue fighting and probably die. Hence glorious death. Nelson at Trafalgar, the troopers in the Light Brigade, all chose the likelihood of death rather than the certainty of being called a coward. A soldier too frequently buys his glory dearly, paying with all he has to give.
That war, and its casualties, might be profitless is a separate question. What has happened as you got older is, perhaps, that you shifted your focus from one question - focused on glory, self-sacrifice and courage - to another, focused on different and arguably better human values.
The concepts of courage, reputation and, yes, glory are still however very much alive in military circles.
That respect for it, though typically military, is not exclusively so is shown by the public reaction to the two policement who (reportedly - the facts have since been disputed) declined to jump into the water to save a drowning child. Every reaction I heard to the initial report showed that the policemen had indeed lost their reputation: the words "inglorious" and "cowardly" were actually used in one newspaper report. No - glory, and glorious death, still seem to be alive and kicking.