This is comparing apples and oranges though. Automotive cooling systems are designed for a very different problem set than datacenter cooling systems. The temperature gradients are much larger in ICE systems, they need to be small, light, and portable, and they cool something that generates much more variable heat loads.

A data center creates a consistent heat load, is stationary, with access to a source of water that is functionally limitless to the operators, cools a much smaller gradient and needs to do so in the most economical way possible to be as profitable as it can be to the owners. Evaporative coolers are dead simple, very effective, and scale very easily which is why they are used.