You are missing the entire point. The Axis specifically Japan needs to be bombing both the Caucasus and Russia. Now Japan may need to increase the number of bombers being sent to Russia due to the increased AA guns, but the goal of the strategy is to choke off Russia’s production ability.
I do not think I am missing the entire point, just because I choose to bomb Caucasus over Moscow. Well obviously if Moscow is only protected by 1 AA gun, you bomb that while you can, but I am just not going to come over to the idea of bombing through 2 AA guns while Caucasus is still available. It’s just a bad gamble, and sure, it can pay off sometimes, but I do not like bad gambles as a strategy, unless things are truly desperate. And I cannot see a situation where getting 16% more SBR damage justifies doubling the risk of getting shot down by AA. If times are that desperate, 16% more SBR damage is not going to save you.
Also I am curious, have you ever won with this strategy against an opponent of equal skill or better? In my games, victory seemed a bit out of reach, so I am hesitant to keep trying it. USSR was losing money to SBR alright, but the extra territories it was able to keep due to the much slower Axis ground build-up seemed to make up for it. Maybe I did not buy enough bombers with Japan, not sure. I stayed at about 3 with them.