No, 2000 racks is not nothing.

But I would say that's a pretty small datacenter, wouldn't you?

The footprint for 2000 racks would be over 1000m2; when you add the necessary spacing as well as supplementary utilities (power/networking) that probably means double that footprint.

I guess at the scale those companies are operating it's not that big, but that's still quite a large building !

I actually have no idea to be honest!