It's not a hypothetical:

Trump started blaming Biden for the US's interceptor shortage two days into the war. Third-party military analysts say there's a high probability Iran's drone stockpile will outlast the US's first-tier interceptor stockpile.

The first-order math checks out: At the beginning of the war, we (and allies) were using 800 x $1M patriot missiles per day. The global production capacity for patriots is 600 per year, so there's no way we've have been able to maintain that cadence now that we're in week 4 of the war (the patriot program has not existed for enough decades). Now we see things like successful strikes on Israel's nuclear complex.

If the math isn't good enough, note that Trump backed down over the weekend, after Iran reiterated that they'd target civilian infrastructure if the US did so first. If we still had adequate interceptor capabilities, calling his bluff would not have worked.