So let's assume that the average person wanting to play SimCity is running a Core2Duo (released 7 years ago). It's hard to find benchmarks directly comparing a Core2 E6600 to something like an Ivy Bridge Xeon that you'd expect to find in a modern dual-socket 1U server, but even looking at a TomsHardware chart of x86 core performance can tell you that an i7-2600k is only about twice as powerful as a Pentium 4 HT660 (core-for-core)
http://www.tomshardware.com/charts/x86-core-performance-comp...Bottom line, the total cost of ownership doesn't at all make business sense to do right now. In 10 years, it very well might.
See also: https://gist.github.com/jboner/2841832 ("Latency Numbers Every Programmer Should Know"). TL;DR
Main memory reference 100 ns 20x L2 cache, 200x L1 cache
vs
Send packet CA->Netherlands->CA 150,000,000 ns 150 ms