I interpreted your "This extra spending is paid for with inflation." perhaps more generally than you meant it, then. "Any extra spending would've led to inflation" vs "that specific extra spending led to inflation" - I read you as more the former, not the latter.

Re: "usually" I'm not sure if I disagree with it because I don't know what you mean. "Usually" in practice or "usually" in possibility? By dollar share or by project share or other? And how directly are we measuring ROI, especially in terms of infrastructure or technology development from large projects?

I believe we could certainly get to a point where most government spending was net beneficial without needing to shrink the services provided by the government.

EDIT: and if we're picking on logical errors instead of getting into more details: my claim was that other forms of spending could avoid inflationary problems. I don't see your response that this would usually be mis-allocation or unproductive saying anything directly about my claim.