As I said... doDiscard is just garbage collection which essentially is the universally recognised alternative to TRIM where TRIM support is not provided.
Support for the actual TRIM command is not there and the impression I get is that there is no interest in implementing it at this time. It is far more likely to appear in the next major release of Mac OS X IF (and only if) it proves to be of value when compared with what's there just now.
Online articles projecting TRIM as some sort of God command for SSDs should be taken with a pinch of salt. Apple isn't stupid. If it throught TRIM was vital to its customers it would have done the same thing as Microsoft since as you say it's to become part of the ATA standards. The impression I have is that there is an arrogance that what's already there is all Apple's customers need.
Bare in mind that Apple likes customers who buy new kit every few years. So the wearing out of SSDs is not something that really concerns Steve Jobs. He expects you to be buying new systems long before the SSD gets a chance to wear out.
