By no means claiming to be an expert in this subject, but I always viewed German intervention in Africa (and Greece) as a political necessity to prop up Mussolini under the premise that if the Italian Leader had failed not only in his new bids at expansion of the Italian Empire, but also lost all their historical possessions (with hundreds of thousands of prisoners taken), the odds of him being deposed by popular uprising would rise dramatically. With Italy no longer an ally, all of a sudden Hitler's flank in Austria is much more vulnerable. Going down this path, although having an unaligned neutral on his border would have been worrisome, what would likely have terrified Hitler and justified whatever investment was required, was not only the fear of popular uprising in Italy, but one followed by the election of a Soviet-friendly Italian government. Even the remotest possibility of suddenly having hundreds of Soviet bombers parked in his back yard withing striking range of his key industry in Austria and Southern Germany was a risk he just could not take.
That's just me....
The potential for an Italian collapse certainly played a part in Hitler's thinking when it cam to intervening in North Africa and even Greece, though less so there.
The problem with predicting what will happen ITTL is that so many things play into the decisions that it becomes hard to decide just how the scales will tip on them all.
For Hitler Barbarossa is the priority long term. The problem is events in the here and now are distracting from that. For a start Italy is looking like it could well collapse if the military misadventures of Mussolini keep going from bad to worse. That has to be prevented if it is at all possible, the question becomes how to do that. The other more fairly immediate problem is the British currently looking at Greece, they are already on Crete and if they get airfields on the continent then his main oil supply is at risk, jeopardising Barbarossa. The annoying thing is the only reason the British are in Greece is because of Mussolini. So what to do.
Well an intervention in Greece is a certainty, it not only removes the threat the British pose but also takes pressure off of Mussolini. It is also a much easier proposition as you can travel there by land so the logistical issues are quite a bit simpler. The question becomes what to do about North Africa. Saving Mussolini's blushes there does have benefits. The issue ITTL is will it be possible, as we stand we are a week away from the OTL decision to send troops. When that decision was taken OTL Britain was camped outside Tobruk and would be for some days. Britain could be at Breda Fomm or inside Benghazi in another week for all the Germans know right now. Every day that passes ITTL without a decision being made to send troops to North Africa makes that decision lass likely. Remember that even though the decision was made on the 11th of January it was not until the 12th of March that the whole of the initial force arrived and that was only a couple of Regiments renamed the 5th Light Division if I recall correctly. The 15th panzer division was not in North Africa until May. Hitler and the Heer have a few things they need to consider ITTL when it comes to sending a force to North Africa.
- How far can Britain get in another month, and how far by the time any German force gets to North Africa in any given strength.
- How strong is the British force because the stronger the British Force the more we need to send to counter it.
- How are the Italians holding up, if they are a spent force they become more of a hinderance than a help so we have to send more as we can't rely on the Italians at all.
Those three points form the basis for the equation that needs to be carried out by the Germans. How strong a force do they need to send to stop the British. How long will it take that force to get to North Africa. Can that force arrive in Tripoli in sufficient strength before the British do . The last thing the Germans want to do is send a force and have it trying to unload at Tripoli under artillery and land based air attack as the British are on the Doorstep.
Right now the speed of the British advance and the apparent size of the British force (as well as the actual size) all mean that the likelihood of Germany being able to successfully intervene diminishes by the day. Germany wont willingly sacrifice units for Italy, if they thing there is a hope for success then yes they will intervene or at least look too. If they think it is a forgone conclusion and they can't arrive in time in sufficient strength then i'm sorry Benito. Now about Greece.
Edit; I forgot to add this bit back in.
The dilemma for Hitler will be being unable to intervene or trying and failing to intervene in North Africa then having that British army jump on ships and Land in Athens, possibly backed up by more British formations. He then has a large, battle hardened British Formation sat in Greece on the Defensive, using the terrain to its advantage and possibly being reinforced by the day. Trying to remove that threat will be very difficult and will use up a lot of troops, tanks and other resources. All better spent on Barbarossa. The lass likely an intervention in North Africa becomes for Germany the greater an earlier intervention in Greece becomes.
That is an interesting scenario where German troops appear on the Yugoslav border in February rather than march and the whole thing is brought forward a few weeks to a month or more or so. In that case a lot of the troops used could then return to Germany and rest, re-equip and perform maintenance before Barbarossa after having fought an easier enemy in Greece due to a much smaller British commitment.