At the moment, a few providers have the scale and skills to run datacenters much more efficiently. But I'm guessing that within a few years there will be some generic datacenter-in-a-container available, with efficiency not much inferior to the big four.
At that point, we go back to the hosting market of 15 years ago. Everybody can offer a datacenter without deep technical knowledge, and sell compute cycles on an open cloud market.
It's like all the tiny hosting providers, except that it requires more capital. So it becomes financialised -- if you can get cheap power, low temperatures and good connectivity, and borrow a few million dollars cheaply, then you're in business. But margins collapse precisely because nobody can do it.
In the end, once we get over the transition period of this move to cloud everything, datacenters end up like utilities