I don't think the reason for Xeons is really that complicated. Think about it this way: when you're running a private server for a couple of friends, a part failing is annoying and costs you $120 to replace (I figure no part of a very basic i3 server costs more than that).
If a large business has their server fail, they are out thousands, hundreds of thousands, or even millions of dollars. They still have to pay the employees for showing up, but the employees can't be productive or work. Time is literally money.
For example, if Anandtech's servers crashed, they would lose a considerable amount of money in due to lost ad revenue as people migrate somewhere else for tech news (perhaps permanently).
This money easily exceeds the cost of even several Xeons--all of which are necessary to deliver content to consumers. Anandtech hundred of thousands of people--that requires far more than a home server, which only needs to connect to 1-2 devices at once.
Now, these parts CAN be used for gaming, but there would be no benefit. Gamers don't require the dozens of threads or terabytes of RAM that servers do, and they see no benefit from ECC protection in RAM.
So, in a way, you are right--there is no point FOR YOU or for any gamer to get a Xeon. A 3570K is a much better purchase since games depends more on clockspeed than threads. BUT there are uses for Xeons.
You're basically arguing that "I have never seen a need for Xeons, thus nobody needs them." You look like King Lear: he believes that because he was abused by his daughters, everyone's troubles must come from their daughters (Act 3, scene 3, search for the line "pelican daughters").