Why couldn't German afford to make 100,000 aircraft in 1938? The Versallies treaty! The reparations payments were less than German was saving by reduced arms expitdures Less than Britian and France were paying in US ww1 war debts..
The British army was smaller and the USA just had a lot industry and resources.
You cannot afford everything priorities have to be chosen. They could have with a smaller army. They decided to motorizes all their flak.