That pretty much describes me and the thing is that even though I still need a PC for the same reasons as you, I haven't felt the desire to upgrade as before. The reason? Pretty much exactly what the article states.
I used to upgrade every couple of years, and maybe slightly more frequently. And, I would see significant performance/productivity gains per upgrade.
But, unlike before, I don't feel any performance "pain" with my current desktop or mobile workstation. They are both 3-4 years old, Windows 7 64-bit machines, and pack plenty of power/memory for my (heavy) use. So, I no longer feel a need for better performance.
Seems there was a time when software (including the OS) pushed the hardware, such that users were ever hungrier for more power. But, now it seems that hardware has gotten out in front permanently for all intents and purposes. A slightly above average consumer rig with sufficient memory can now handle just about any task most folks will throw at it and with relatively no latency.