10-15 degrees is all you need to keep a "cold aisle" at 85degf, most places, on the worst day.

IIRC Amazon figured out that individual components could actually run hotter within an acceptable replacement window.

higher equipment replacement is more than offset by the fact they don't have to do refrigerant based cooling which makes daily operation ridiculously cheap... no pumps or complicated mechanical devices to produce cooling... no people with special skills to maintain them, etc.