[Alan Roehrich]

You don't have to turn more RPM, which reduces the life cycle of the rest of the components, and requires other expensive changes to the car. You can always go to a more aggressive cam profile, if possible.

If nothing else changed, yes, a reduction in valve weight could result in an increase in the life of some components.

But do you really think that nothing else will change?

If one guy uses the reduced valve weight to make a performance gain, then the rest, at least those who try to remain competitive, are forced to follow suit. Automatically negating any gains in reliability or reduced cost.