Then the SS dies in France...
Murray makes a point as far as it goes, but this still misses how the Allies with a more difficult position managed to not have their supply route interdicted & were able to build up in the face of the Axis air forces.
for the reasons I stated. The Allies had complete control of the Med, and could bring in transport ships as far east as Bone. The Axis could only bring in (after the initial first couple of months) supplies by air.
The US Army was the best equipped and most formidable corps of engineers in World War II (and since for that matter) and could and did build new airfields or upgraded old ones within a couple of months of Torch. The US and British committed 2 US Air Forces (1 tactical with fighters, light and medium bombers, 1 strategic with heavy bombers), the Desert Air Force (which was significantly larger than the US commitment), and had essentially unlimited access to spares, fuel, replacement aircraft and aircrew.
Meanwhile, the Axis had to flew nearly everything across 300 miles of sea. Over 600 Axis aircraft were captured at the end of the campaign that were sitting on the ground as they lacked spares and fuel and had been cannabilized to keep other aircraft operational.
Logistics was decisive in this fight. So was the fact that Allied fighters shot down around 500 air transports over the course of the campaign, as the Axis lacked sufficient fighter strength in the area to properly escort their vulnerable transports (read about the Palm Sunday Massacre as an example).
Even so, Allied losses were around 850 aircraft vs 2250 Axis (that includes the 600 captured aircraft and 500 transports downed). Only 40% of the Axis air strength was German. The Axis high command could not have picked a worse place to fight an extended campaign.
But in France and Belgium the Germans have essentially unlimited airfields, easy rail access to Germany, plenty of local labor (another issue in Africa), excellent facilities (which they lacked in Africa), and even a local aircraft industry (French aviation industry was put to German use during the war).
While of course having better fighters in 1942
The Allied Air Forces also had some serious issues with doctrine (read An Army at Dawn which discusses this, as do several other works), and weather was terrible November - January in Tunisia.
Economy of Force is a standard military technique. You can't be strong everywhere, as there are always more missions than resources. Not even the Soviets could be strong everywhere. So you conserve assets in less critical theaters like France in 1942 to have more resources available to attack the Soviets. Everyone uses economy of force.