Racking Mac Pro (trashcan) in a Datacenter

That's cool and all but how on earth is it not more financially advantageous to just port their software to Linux and run it on commodity hardware?

This is staggeringly inefficient. Not just in the cost of the hardware, but all the lost time spent designing this rack system. Not to mention the costs of performing repairs. Macs are not designed for maintainability.

Despite what seems like a comical waste of space, this does have 4 systems per 4U chassis, which averages out to 1U per system.

(Though I'd also suspect the actual guts of a Mac Pro could pack much more densely than 1U each in a blade-style form factor.)