There were only two lines producing P-38's, they were right next to each other. One bomb in the right place would have wrecked all sorts of stuff. You're talking about the most complex and difficult to manufacture prop fighter of the war. EVERY assembly had to be done on special jigs and fixtures. EVERY operation where two assemblies were joined had to be done on special jigs and fixtures. There were VERY FEW spares for those jigs and fixtures. That's why the P-38 was never adequately second sourced, there was barely enough tooling, jigs, and fixtures at Lockheed. And that is why the War Production Board denied Lockheed shut down time of any significant length.
The Germans second sourced all sorts of stuff. As strategic bombing reach further into Germany and did so more often, the Germans actually moved production of parts and assemblies into smaller shops in areas less likely to be bombed.
See the difference? ONE source, with only two production lines, right next to each other, on a more complex aircraft, all in one location, compared to multiple sources in various locations, building the parts for a far less complex aircraft.