@parados,
I think you missed the whole point of the Laffer Curve concept. It doesn't begin to tell us what taxes will be, or what they should be. All it does is observe that for any
given revenue desired, there are two rates that will yield the same revenue,
ceteris paribus.
The assumption is that the higher rate will slow down an overheated economy, while the lower rate will increase economic activity. Now, this is an assumption, but I doubt you can dispute it.