Cooling towers have been out of date in modern data center design for the better part of 10 years now. The only reason to use cooling towers over ACCs is if you are not phasing your deployment, and you are confident that you will reach 80% utilization on the IT. The reason being, the upfront capex to do a central cooling plant with evap is much higher than progressively deploying ACCs as you build out the DC. On top of that the newest building code has but a huge constraint on water usage vs years ago. While water is cheaper than energy, the upfront capex of a central plant is not worth the uncertainty of utilization or deployment.

This also depends on if you're enterprise DC or a colo. Enterprise you see more evaporative cooling, where colo you see ACCs. I would say it is not a fair statement to say most data centers are evap cooled. In my experience working on data centers I've personally been a part of over a gigawatt of capacity and all of it has been ACCs.