What, more air stress on the filter?

Depends on the type of racing, top fuel drag racers rebuild their engines as frequently as every 30-40 seconds. Dakar racers have engine swaps daily. It is not a myth - it is fact.
i'ved never seen K&N's fitted as standard - care to name nd shame as it might shed light on the reaon behind this.
Interesting point,but a flawed one. Lets just suppose they do (which I doubt in all honesty) you are forgetting that a typical DTM race engine will likely do less than 2000 miles between rebuilds.
How many miles will an F1 engine do before a strip down do you think?