Don't believe everything you see or read
I was reading some literature that was touting the use of an overhead power distribution system. It made its case for overhead cabling mostly by pointing out the potential risks related to restriction and obstruction of airflow as the result of leaving abandoned cables under floor and not having an organized cabling system. And then to drive their point home they showed a couple of pictures of removed raised floor panels with a Rats nest of cables beneath.
In one picture all I could see was a mish-mash of network cables with no discernible organization system. The other photo showed yet to be installed power cables coiled and stored under a one-foot raised floor.
I don't know of any new data center being built with a one-foot raised floor. And the same can be said for visiting a data center with a Rats nest of cables under their floor. Obviously these pictures were selected to prove a point, but if these are real data centers in operation today, I think they probably have bigger issues than cable management.
I'm not knocking overhead power distribution, our power cables are placed overhead all the time. But I'm not about to criticize the majority of all data centers that utilize raised floors as their platform for power and cool air distribution system. It works too well for too many data centers to be so misleadingly criticized.