1) The US has run 13,000 missions over Iran in the last month. Thats a lot of targets.

2) The initial US degradation of Iraqi capabilities was much much greater in gulf war 1.

3) F15s are not stealth fighters.

4) This is 35 years later.

5) "strategic bombing" of air defenses is mostly accomplished with our cruise missiles. We'll take out any air defenses we find, but you don't fly non-stealth planes over SAM batteries intentionally.

We haven't even started a ground campaign. If one plane is downed per 13000 missions, I think we're doing ok.