Actually, I disagree.
The Nazi's learnt all the wrong lessons from the Spanish Civil war. This is where survivorship bias really kicks into place and the Germans took the wrong thing:
1) The Republican Spanish were armed mostly with I-15's. (See Diagram below)These feckers gifted to them by the Soviet Union. Let's be honest, These things weren't going to prove any useful against Bf-109's. Ultimately the Soviets sent these as a testing ground of how well their aircraft would perform against modern western European aircraft (Hint, not well at the time). So, the Germans basically thought that their designs were impeccable and didn't really iterate beyond the Bf-109's until midway through the war. Instead they tried to perfect the Bf-109 and lead to about 8 variants, some of which were very good but others were pretty poor by the mid-way point of the war. It wasnt until 1942 where the Fw-190 really began coming up in numbers.
Partly, the Germans were right in their assumption of dominance; The French practically had no functional air force and Britain hadn't begun full re-armament yet. But they did not stop to really push forward their advantage until just before the war began and it wasn't until halfway through the way later iterations started going into the mass production.
2) The obsession with Dive bombing.
It was actually the Americans who were the first to truly adopt dive bombing during the inter-war period, as the British didn't believe in the cost/benefit analysis of danger to life and tactical use. The Americans conceptualized it almost solely for naval warfare.
During the Spanish Civil war, the Stuka was very impressive, however the reasons they were impressive were not factored into Luftwaffe consideration.
-The Stuka was fighting against an opponent without a real air force.
-The Stuka was fighting against an opponent with practically no real anti air defenses
- Fighting was concentrated mostly with un-mechanized and motorized group units, at some points in very dense formations.
Why did the Americans use dive bombing against ships? Ship anti-air defense is concentrated, to a very small degree of the battlefield. It is very intense therefore survivability in these conditions actually improve when the surface area of the plane decreases. Second of all, fighter escort organization in carrier -> carrier warfare was very chaotic and messy. It's much easier for a squadron of Dauntless to drop from altitude onto a concentrated group of ships without having full interception attempted. Finally, Ships are relatively large targets even when moving. The increase in accuracy of dive bombers is worth it because you turn the calculus from "probably won't hit ship" to "probably will hit ship".
That calculus all changes in Land warfare. First of all, Interdiction and Interception is far easy to co-ordinate from airfields on the group with multi squadrons. Therefore dive bombers are more easily intercepted. Second of all, Flak fire is far more distributed and less concentrated, which makes the relatively survivability of a dive less important because the reduction of the surface area is negligible when the fire isn't concentrated in one place anyway. Third of all, increasing the accuracy with a dive changes tactical level bombing from, "very unlikely to hit a moving vehicle" to "still very unlikely to hit a moving vehicle." The trade offs just simply were not worth it.
The dive bombers Germany used in Spain had absolutely awful flight characteristics, but they never learnt that lesson because there were no capable Republican fighters to actually exasperate this problem. Even in the peak of the Luftwaffe, in 1940 during the battle of France, a squadron of 6 early 30's P36 Curtiss' intercepted a squadron of 12 Stuka's and destroyed them in 6 minutes.
Because of the success of the Stuka in Spain, Luftwaffe leadership made stupid requirements that impeded a lot of their designs. Being that all their tactical level bombers must be able to dive. Even the 2 engine medium bombers like a Heinkel 111 could dive. It meant sacrificing a lot of flight characteristics. Heck, even their Fw-190 primary late war fighter could dive bomb, a requirement that is wholly pointless. A lot of compromises in Luftwaffe airframe design occured because of the wrong lesson learnt from Spain - that dive bombing is king. The Americans took the right approach, and Fighter bombers like the Mustang didn't need the stupid flight characteristic skew to enable dive bombing, but instead had more linear bombing trajectories, which although meant they were less accurate, they could do their main job absolutely much better. The differences between dive bombing and linear trajectory bombing was also really small in terms of efficacy. They had dedicated dive bombers for that, like the A-36 and didn't try to attach dive bombing onto everything.
3) The lack of a dedicated heavy bomber
The Germans bombing of UK for example, was very inefficient because they lacked real heavy bombers like the Allies had. One of the biggest reasons for this is they saw the performance of their medium and dive bombers in the Spanish civil war and decided it was enough. Again, Spanish civil war was an aerial peashooting competition but they took the wrong lessons. It wasnt until the He177 until the Germans had a functional heavy bomber because medium bombers just couldnt do the trick when it came to strategic bombing.