Manufacturing ordnance just to blow up caves in Afghanistan that the USSR already just spent 20 years blowing up doesn't yield fruit - the materials and labor on both sides quite literally goes up in smoke.
Simply, it is absolutely the case that wealth sometimes gets destroyed rather than merely transferred. Sure, the fiat dollars might "just circulate" but that's an uninteresting, trivial tautology. When people talk about "losing money" in the general case, the meaning of those terms transcend the pedantic, trivial case that you espouse.
When the whole world gets feverish over an investment fad that's doomed to fail, "spending money on it" really means "allocating vast resources in the hope that we all get a return on that investment". If we don't get any return, all that investment truly is lost - destroyed, even. There have been cases where we (the humans of Planet Earth) had wealth that we could have done anything with, we chose to put it towards something that didn't work out, and now it's just gone.
(To be clear: I don’t think AI specifically is valueless)
This is false and a dangerous rabbit hole of an ideology to get into.
Money is just a medium or technique to enable this whole economic process. It’s not important here.
The only way AI can turn a profit is from a government bailout.
In fact, money is printing every day more and more. So technically there is more of them every day. Which decrease their value and then we have inflation.
What does cause inflation, however, is when more dollars are printed versus things being made. You can't precisely measure the latter, so you have to make do with price indices and such. Which makes inflation hard to actually gauge, especially when everyone expects more and more to be produced every year (i.e. they expect their savings and investments to appreciate/gain interest) so you have to print more dollars to at least keep up the facade.