It's not easy to get rid of alpha test. Hardware must support all the applications written using DX9 or GL1, where this feature is present and used extensively. Therefore, some hardware support is expected to be there for some time...
BTW, ATI R6xx-R7xx cards (i.e. all recent ones) support alpha test too, see:
Radeon R6xx/R7xx 3D Register Reference Guide, page 126
Radeon R6xx/R7xx Acceleration, page 7, section 2.1.4