Master's degree in Holocaust and Genocide Studies here.

First, you should probably read Mein Kampf where Hitler details his beliefs more on this subject, but the scapegoating of Jews as holding Europe's money strings goes back to the middle ages, where Christian law often forbade money lending with interest, thus pigeonholing Jews into this profession. No one likes the IRS here in the US, and it was similar in this regard with view toward the Jews and money over centuries. The blood libel just added to this long history of Christian anti-Semitism.

Let's fast forward to World War I. The Germans had defeated Russia and gained a ton of land. But the Americans enter the war and the Ottomans & Austria-Hungary surrendered. Without allies and much reserves, Germany signed the armistice ending the Great War. Thus began the Stabbed-in-the-back myth.

And remember in your quote:

then the result will not be the Bolshevization of the earth, and thus the victory of Jewry, but the annihilation of the Jewish race in Europe!

Hitler is equating Bolshevism with Judaism. Many secular Jews had experienced so much anti-Semitism in Europe, that Communism was appealing to some. Key word is some. To many others, especially deeply religious Jews, Communism was never appealing. But many anti-Communists were happy to paint the picture that Trotsky was Jewish and were happy to elevate any notable Jewish Socialists they could find. Even non-notable Jews . . . with terrible consequences.

Hitler saw Bolshevism as a movement that would threaten borders, an ideology that was bound to spread throughout the world. Many proponents of Communism, also wished for this goal.

Keep in mind, he made this speech at the beginning of 1939, before the non-aggression pact was signed with USSR in August of that year.

So my answer would be that there was a long history of anti-Semitism in Europe that targeted Jews with controlling money. Combine that with the fear of Communism in a post-Marx world and it gave Hitler with a casus belli in the eyes of his deeply indoctrinated supporters and sympathizers.

I apologize on my alternating the terms of socialism, communism and Bolshevism. I used the terms where I thought they were most appropriate.

I've been working on this and the broader perspectives of this question for a while. I'm pretty sure the answers address a good portion of the modern hysteria concerning "conspiracy theories." I'm going to directly answer your question and then move into a broader relm as I would like opinions on this as well. Hopefully all this qualifies and doesn't get deleted because so much written about this subject is conjecture and whitewash, and incredibly hard to cite, IMHO.
The Nazi's used a historically prevalent form of racial and cultural xenophobia to vilify the Jews, as I understand, the Ashkenazi Jews in particular. They were able to do this under the hysteria created by an opposing philosophy in the east, years of racial and cultural propaganda and the low morale of the German people after WW1. The "Jewish" financiers was by no means new rhetoric. Personally I believe this particular mindset goes with the whole usury argument, that during the renaissance and earlier, certain Jewish communities were later able to found the world monetary system since they had a leg up on finances in the region thanks to being able to handle money when Christians couldn't. Whether or not this is true, that idea has been used to stir emotions for quite some time. Enough so that pieces of fabricated evidence have been created, such as the Protocols of the Elders of Zion, which had long been proven fake before WW2. Still, the particular type of xenophobia persists today. As far as the Bolshevization bit, a philosophy so different and carrying such implications scared the German people enough that they were willing to turn towards mob mentality as had already been done, using these variables several times already, specifically the pogroms. Here's where it gets a little more opinionated, although I hear of a Norwegian history professor that is making these same claims. The hysteria used by the Nazis in this instance is one of several instances using fabricated and non-fabricated propaganda coming out of and as a result of the French Revolution and the ease of disturbing information. Personally I think that most all the hysteria surrounding the "Jewish, NWO, Illuminati, Masonic, Rosicrucian, conspiracies" comes first from the imperials reaction and then in turn from the industrialists reaction to the ideas of the French revolution, first Democratic Republicanism and then later Anarcho-socialism. Take Germany right before WW2, using old half-truths put out by the imperials against the french revolution to paint the socialists (Jewish) as murdering anarchists, which kinda came true to some degree. Of course that information was first used by the imperials to paint democratic republicanism as a greedy murderous form of government perpetrated by Jewish financiers that actually wanted to take over the world. Which financially from the imperials point of view, they did, though not exclusively Jewish. I hope that's not too off topic. http://en.wikipedia.org/wiki/The_Protocols_of_the_Elders_of_Zion, http://en.wikipedia.org/wiki/Ashkenazi_Jews

In addition to other comments, one must remember the Nazi economy in the 1930s was not the 'miracle' of Nazi myth (that still has currency today), rather it relied on some very creative financial tools to basically print money (such as 'mefo bills'). From 1938 the Roosevelt administration was increasingly critical of the Nazis, and Hitler was sensitive about the actual parlous state of the German economy.

Hitler's foreign trade system relied on convincing partners to take Reichsmarks, and the US was not in favour of this. Since many of these partners were in South America, it was a point of friction.

A good source is Wages of Destruction bv Adrian Tooze.