I'm a "build it myself" guy, have never bought a prebuilt PC over 20-odd years. But I agree with Andrew H. in that you are rolling the dice every time you do it in hoping the pieces you bought do work together and are not faulty. There is *always* that fingers crossed moment the very first time you switch it on. When it works, brilliant. If it doesn't - any satisfaction you may have gained goes south very quickly in the painful hours of diagnostics, scouring forums, returning parts, waiting for replacements, retrying hoping that fixes it, yada, yada, yada. As a "one-off" exercise which most of us do it as it is very much a false economy for anyone kidding themselves about saving money.
As for that "kid down the block" - well I used to build for friends and family but vowed never again many years ago. It means you become their "free" lifetime support guy, a novelty which wears off pretty darned quickly when you ain't getting paid or have other things to do with your time. I always direct them to buy retail now.
Getting back on topic - I think some people are over-reacting to this Intel rumour/speculation (which is all it is from what I saw). As others have said we don't *know* anything for sure or how widespread across the product range if it is even true. Personally it really wouldn't bother me to not have CPU upgrade capability, as in 20 odd years of building PCs I have not once chosen to do a CPU upgrade alone. I always want the latest and greatest, and thanks to Intel changing the sockets every frigging time that means a new motherboard anyway. Or other stuff forces desire for a motherboard change - like USB 2.0->3.0, AGP->PCI-Express, memory chips, UEFI bios, form factor size changes and so on.
Storm in a teacup I say.