Look at the current state of Mackintoshes. People are having kernel panics and struggling to keep their machines running with current software. OS X moves pretty fast, possibly faster than Linux, and Apple builds it to support Mac hardware.... the teams who are porting hackintosh code have to support a lot more hardware variety and they have less resources than, say, linux.
Running mackintoshes in production makes no sense.
And I challenge the claim that you would save money.
Looking just at off the shelf costs of low end hardware does not tell you the TCO of serious machines that need to be running all the time.
To get comparable hardware quality to Apple products you have to spend more, generally, when going with "commodity" hardware.
The idea that Apple is expensive is a myth, born of two things-- people perpetuating it since 1980 (yes, 35 years this myth has been spread), with the vested interest of rationalizing their dislike of Apple... and the fact that Apple doesn't compete at the very low end.
In production, TCO is much more about reliability and other things than initial hardware cost.