Yep, if the army had the will to overthrow Hitler in 38 or dictate to Goering in 1939, the 20th July 1944 plot wouldn´t have been a plot on 20th July 1944 but a successfull coup in March 20th 1943, after Hitler suffering some kind of "accident" or victime of an allied assassin.
With them in power, offensive against France/Belgium/Holland probably won´t happen, in 1941 the Anglo-French alliance invades the Rhineland and they start to backstabbe each other to surrender first. May 9th 1942, Germany has surrendered to the allies. A few years later the Anglo-French pick a fight with the Soviet-Union, in the belief the SU is weaker than Germany was, a few more years later the Red Army is occupying France, the two first atomic bomb ever used in war hit London, many more follows.
Indeed by 1939 overall German living standards had fallen since 1933
Certainly the German economy had its weaknesses but this? Nope, that is simply flat out revisionism.
Himmler just isn’t of the same calibre. He was totally inept at political plotting and the only other top Nazi who really hated him and tried to undermine him was Bormann whose rise to prominence started with the departure of Hess.
More important, even if he did have the capability, he simply wasn´t interested in seizing power, leaving that to Hitler and Goering to focus on his existing projects.
There's also of course, the matter of the economy, how exactly does Germany's economy stay afloat without looting Czechoslovakia and Poland?
Boheme-Moravia had industry and that was a nice addition but its use was less than half-assed* for the first 2 1/2 years, all while Germany itself had much more industry/infrastructure.
German population back then was over 80 millions, today the population of the Czech republic is barely 10 millions. Hitler wanted Czechoslovakia gone before dealing with Poland and Bohem-Moravia to become a German region, as part of his lebensraum policies.
Poland? What exactly did the approx 2/3 of Polish economy that went to Germany have to contribute to Germany, that compensated for the occupation costs? Hitler spent more in the Luftwaffe than Poland in
all of its armed forces, even the local transport infrastructure had to be beefed up for Barbarossa, the country was an economical dwarf.
How about the United States economy today running on France´s industrial capacity and Mexico or maintaing its 1947 economic standars by looting occupied Japan? Utterly ridiculous of course.
* The idea of Hitler seeing the protectorat as a vital economical tool kinda negates an important part of his racial beliefs.