No, that's not what he said.
Tolwyn said we should not need using it at all.
AA was designed to get rid of 'steps' at low resolutions (ie like 640x480)
At the high resolutions we are running nowadays, there's no longer speak of 'steps', but mear 'jaggies'.
Hence, acccording to theory, we can do without AA...
What it boils down to in my opinion, is that we are all so 'spoiled' in not wanting to see any jaggies at all.
(Me thinks there's people that'd even use a magnifying glass to make sure there are none left after the latest new HW upgrade, driver and settings tunings...)
Just think about the huge task AA has to perform, for each and every pixel drawn, it has to analyse whether it is part of a straight line, and if so, it has to change contrast and whatnots of pixels around it, to try and solve the jaggie issue. To smoothe it out, AAx4 does it probably with double the amount of work ('depth'?), even more for the x8 etc.
Now, remember, we are running high resolutions... so, for each and every pixel...yeah. Sh1tloads of work... performance will go down .... alot...