Getting more power into a datacenter is a different problem than getting more (already available) power into a rack. I suppose I could have added "if your existing power distribution system can handle the extra power capacity". That includes service entrance, transfer switching, standby and backup power sources, and distribution to the rack level.

The point I'm trying to make is that, all things being equal, it's _much_ easier to handle un-equal power load between individual racks than it is to deal with the cooling side of the equation. Adding more power to a single rack usually just means a few more whips from your distribution. Getting that one extra-hot rack in the aisle to be effectively cooled requires a lot more infrastructure than running some cables.