Why are datacenters built over a wide area instead of using taller buildings?

I've seen a lot of datacenters pictures and it seems that the owners prefer to build them over a wide area instead of building them using taller buildings. Why?

Because they don't need to be located somewhere land/real estate is expensive.

Tall buildings are cost effective when the expense of the structure is less than the cost of the footprint.

I'm guessing its due to easier cooling, better weight distribution, cheaper land costs, and ease of moving equipment around. Hot air rises, after all.

Well, because they're data warehouses. And warehouses are single-story. Makes sense to me.

I've been in multistory data centers. And I'll bet they are all the rage inside big cities. I'm no construction engineer, but I suspect it is cheaper in most areas to use a bigger footprint than to build multiple stories.