What a fool Buchanan is.

Why did Hitler start a war without a surface fleet? Uh, he had one. One large enough to keep a substantial portion of the British fleet at home, out of fear that the Germans would sally forth with their pocket battleships and heavy cruisers.

Why didn’t Hitler build strategic bombers? He and his top brass were convinced that they were unnecessary, and that bombers needed precision dive bombing to be effective. Additionally, his high command did not forsee the necessity of bombing the armaments factories in the Urals, once Germany engaged Russia in combat. This is covered in great detail in the fantastic and authoratative source on the subject; The Luftwaffe War Diaries

Why did he let the British go at Dunkirk? He still did not believe war was inevitable with, nor did he WANT war with Great Britain, a nation he saw as a kindred spirit. There is strong evidence that he believed that crushing the Brits at Dunkirk would so harden British opinion that he would no longer be able to persuade the British to seek peace. It was an awful misreading of the British mind-set, even though the Brits had doubts about their ability to prosecute a war against Germany on their own at that time. Additionally, peace with the British would have freed up substantial military resources for the effort against Russia, which was already in the planning stages.

Apparently Buchanan has never actually read any military history books about the period.