Recapping what some others have said, and adding in from my own experience:
It's GOOD if your memory usage is high, your CPU usage is high, and your disk usage is high. That's a balanced system. If one of them is high and the others low, your system isn't balanced and you could make changes (hardware, software, or configuration) to work more efficiently.
The article compares cpu usage between machines without giving work load. If the older machines have lower cpu usage than newer, and all of them are being provided work units as they are available (it sounded from the article that it might be a transaction farm of some sort, not interactive desktop usage), then the older machines are being bottlenecked by something, perhaps something that isn't being measured.
(Side note: I've performance tuned transaction billing systems for national phone companies, cramming shoving millions or even billions of work units through systems. I'm not trying to brag, merely indicating that I'm not talking about what I see on my desktop system.)