Certain important people need to keep selling spyware, drugs, guns and war to keep themselves and their associates employed. As for whether the funds or the actual work (conflict) available is sustainable is for everyone including the accountants to consider.
The other problem is that war doesn’t really die, we just displace where we choose to fight, and how, if we imagine physical and cyber world peace for a moment, for the USA or China to reduce its military capacity by one third, or one tenth, we would see absolute chaos, thousands unemployed, the losses in maintenance and equipment, military supplies, medical, etc, nobody would win.
Any complex society where financial and other systems operate needs a minimum degree of social enforcement to maintain. Whether that can change like a function or is something that depends on a country’s GDP is another issue.
Just consider that humanity would either need lots of free time, energy and money or it would literally need to feel incredibly threatened by something on earth, which we all could not fight to control in order to actually fund going to space or even the moon, and I doubt a triple whammy of pandemic, food shortage or severe draught and floods could do it, it happened in the Bible and people literally just found more dumb reasons to do more dumb things, and no lowering mens testosterone or telling guys to shave more often wouldn’t do shit either. If people don’t find reasons to explore or learn, they find reasons to fight/play fight, it’s pretty normal, and if anyone remembers their childhood, usually it’s pretty much the same across generations.