1930s Germany had no "will" for a protracted war period. That didn't change until the USA entered the conflict during December 1941. By then it was too late for Germany to establish the industrial and training base necessary for a large force of heavy bombers. From 1941 onward most German war production was required just to maintain 200 or so Heer divisions in combat, along with their supporting Luftwaffe fighter and CAS units.
Exactly. Which makes the whole question regarding whether or not the "He-277" was worth perfecting a moot point. To have had a fully adequate force of heavy bombers (or dedicated long-range maritime bombers), the entire "Bomber A" program should have been given a higher priority and not be focused on "advancing the state of the art" so much. The USA and UK did just fine with late 1930's technology in the Lanc and B-17 thank you very much.
Speaking of jury-rigged heavy bombers, I've always wondered why the RLM did not promote the He-111Z as a possible long-range offensive maritime bomber. From everything I've heard, it was an amazingly successful adaptation, based on a very reliable and successful medium bomber, was available (in the form of He-111 components), and - other than the zwilling concept itself - introduced no radical and unproven innovations.