You have it right here. The IRS withdraws often at the last minute because they know they will lose. There are many many cases which would have been wins if the IRS had not run away.
In this case, Cryer is a gold medal trial attorney. The IRS brought in their big guns, tried to taint the jury pool, tried to bar evidence and statements, tried changing the argument attack and throwing in distraction after distraction.
Cryer beat them because he is experienced but he said that others without his trial experience would have been beat.
And yes, the Income tax as applied is unconstitutional.
If you have a high speed internet connection, study this film (easy to watch):
http://video.google.com/videoplay?docid=-1656880303867390173
You seem to be confusing cases like this case, where Cryer beat the criminal conviction, with the underlying issue of the unconstitutionality of the income tax. Nobody has won on that. Nobody.