Not every chance. A small reduction in probability. The key word in my argument that you're not addressing is that they made a tradeoff.

The probability was small in the first place, so throwing it away was a small reduction in probability. But there was no chance at all that Germany would conquer all of the Soviet Union in one step. Especially while fighting inefficiently, also fighting in the west and distracting themselves with other things.

And throwing one thing away to pursue another is a tradeoff. I just pointed out one tradeoff that they made, wich I consider inconsistent (for the reason stated in the grandparent of this comment).

We started out by considering their success in terms of their own goals and under the assumption they were being rational.

Consider it under their goals: Of bloody course. Assume that they were rational: That's exactly what I was arguing that they weren't. It doesn't make any more sense to assume one side of the argument than the other.

assume ... that they didn't believe in their stated anti-Jewish goals at first ...

I'll expand a bit on that if you don't mind. There were two (sets of) reasons why they hated the jews.

*1) Their biological beliefs, where the jewish race and the aryan race were "natural enemies", and the aryan race could be diluted by the jewish but not vice versa. For that reason they wanted to get jews out of every significant part of society, and prevent them from crossbreeding. That goal could be pursued by genocide, or by isolating jews in ghettos and keeping others from associating with them. The nazis did the latter successfully in every place that they controlled before they started on the final solution. Jewish leaders were quite willing to cooperate with the nazis in this matter, because they got more power in the ghettos than they had in the outside society.

Isolating and concentrating jews was probably a necessary stage before extermination. And once that was achieved the jews were not a significant threat (even from the race biologist perspective). People very seldom revolt purely because of bad conditions. They revolt against change, of which there is very little in a ghetto. And while they were kept around they were an economic asset. But once you upset the boat by starting the killing you risk getting revolts. As they did in several places.

*2) They wanted an outgroup to spread hate and fear against. And the jews came in handy, again for two reasons. First the nazis already wanted to hurt jews because of 1). Second it was easy to rile the germans up against jews due to widespread christian antisemitism. For that reason they did a lot of antijewish propaganda (as you referred to earlier), some related to 1) and some being pure lies and fallacies. It also meant that they had to give the appearance of a continued campaign against the jews rather than just doing the minimal to solve the problem in 1). But spending one bullet or one drop of fuel beyond what was needed to appear credible for the proles for the purpose of 2) was irrational.

But since the nazis kept talking and thinking about the propaganda in 2) as their reason for their actions in 1) they felt that they had an urgent need to continue with the genocide. Even when that hurt their original goals.