I think it's a little more complicated than running more cables. Most datacenters have a total capacity they can handle, based on how many connections they have to their local grid (or grids, as datacenter places like Santa Clara have multiple power grids to give datacenter redundancy). You need to make sure your internal power distribution systems can actually handle the amount you want to push through, and you need to ensure that your backup power is actually enough to get you through major outages.

AWS, as an example, tends to only have 20MW to 30MW for each of their datacenters- anything above that they say isn't worth the hassle when they can just open a new datacenter. Power is definitely a limiting factor.

Yes the whole getting more power into a datacenter is much easier to add than the extra cooling capacity to remove that power once it has transitioned into heat. But I'd imagine they would plan and monitor that aspect and may even have redundant cooling systems. But certainly a potential gotcha and one that would soon sort out the bad datacenters when they end up seeing all there hosting overheat and offline.

I think this is also a paradigm problem. Modern chipset advancements are at the crossroads of power vs. cooling. The logical extension of that fight is greater power and cooling requirements in the DC which it is not necessarily equipped to provide by default.