Yes and no. If just formally calculate, yes, servers are small market volumes. But, they are much less constrained financially, than private person, so from same fab one could earn much more money if sell to server market, than if sell to consumer market.
Plus, space arrange could last years.
Heat dissipation in range of megawatts could be just prohibited by local regulations.
So, space in large cities is very serious problem, and for business it is usually easier to "compress" as much computing power as possible in one rack.
There's little need to put large datacenters in downtown Chicago and Manhattan.
Surely you don't believe that the entire chip industry had not thought of "wait what if we just make the chips bigger".
Also big problem - connectivity - you cannot place DC where it cannot be connected to power grid and to very powerful network.
So yes, DC floor space is severely limited.
And the third issue - last decades, rack servers dissipate extremely large amounts of heat, I hear numbers up to tens Kilowatts per rack, which is just hard to dissipate with air cooling (as example, all IBM Power servers have option of liquid cooling, but this is totally different price range).