Binning CPUs on clock frequency or number of functioning cores is a bit different. If you compared it to a precious metal, the higher price CPUs have fewer imperfections, therefore they cost more. The fact that they carry different product numbers is a bit misleading but the price segmentation actually makes sense.
The binning is a bit arbitrary, hence overclocking. A large proportion of parts that are binned to a certain clock speed will perform perfectly well at higher clocks. Bins are decided and priced based mostly on marketing rather than fab yields.
Intel disable a lot of features on low-end chips, which has nothing to do with yield management. There's no technical reason to disable vPro and Turbo Boost on Core i3 chips.
We have both Xeon and i7 workstations in my office and functionally there is no difference, except that the Xeon ones cost 2-3x more. ECC support is not exactly worth it for a normal workstation use.
