It is a common problem. People read the i7 or i5 CPUs may be capable, then get a motherboard that says it can support DDR3-2800+, and DDR3-2800 RAM thinking it will be plug and play. WRONG.
For DDR3-1600+, Intel already considers it overclocking, so manual configuration is necessary. Depending on the specific CPU model, the true DRAM Frequency limit varies. For the i5-3570K CPU, it is DDR3-2133. For the i7-3770K CPU, it is DDR3-2400. For extreme frequency like DDR3-2400+, advanced overclocking experience is necessary to test the CPUs capability and to configure the settings for a perfectly stable system. Again, Intel states ALL processors are only capable of DDR3-1600 max, so you can imagine why DDR3-2400+ is not plug and play. Extreme hardware is intended for extreme power users, it is not for the average system builder, so if one chooses to purchase extreme parts without sufficient knowledge, they better be ready to do some extreme research to catch up and get an idea of how to use their highly advanced hardware.
These top kits are very, very low in quantity. Sometimes 1-2 kits a month, so it is not a mass production item. There is a reason the price is so high, only a few special people will have them around the world. It is not for anyone. The person to buy this will already know they have a CPU tested capable of DDR3-2800+, which is why they want this RAM to push even further, achieve even better results, and hopefully surpass current world records.