So when I ride a bike the fork is locked into a straightforward position and the only way to turn a bike is by leaning?
Upper headset bearings usually do last a very long time, but it's the lower headset bearings that take all the pounding, and they are located in the second dirtiest area of a bike, at the top of the fork where the front wheel sprays up road grime.
Is this why they sell so many after-market headsets is because they don't wear out? and people are just replacing them for fun because they have nothing else to do with all that stimulus money setting around? Is this why they make replacement bearings because they never wear out?
Had you said there is no difference in performance between an expensive headset and a cheap one I would have agreed with you, but I don't agree with what you said about wear. The big difference between a cheap and an expensive headset is maintenance and durability.
And Cane Creek 110 headsets took a step further than anyone else in that the design of the headset supports the steerer tube better due to the compression ring they use, not to mention more seals than any other headset has.
But some of what you said can be correct, in that a good mid-grade headset like the Cane Creek 40 series can last a VERY long time as long as you keep up on the maintenance.