I'm not in the field, but I have seen some of the work done by thermal engineers designing new server systems, and no that's not the case. Cost, noise, and phy

I'm not in the field, but I have seen some of the work done by thermal engineers designing new server systems, and no that's not the case. Cost, noise, and physical box size are to be minimized, and various compute/storoage/io capacity are to be maximized. Component placement and orientation relative to one another, baffles, fan characteristics heat sink design, all play a role. They don't just throw parts in a box and add fans until all components are within operating temperature. Gross air flow is one lever, but it has costs and limits like all the others. Designs are modeled with heat and fluid simulations.