Jake, I'm right there with you on your analysis. The only thing about point #2 you make there is - if Armstrong fought every other allegation, every time, no matter who brought it, why stop this time?
My guess - and again I'm a huge fan of his and this is admittedly pure speculation -
modern tests of his past samples reveal evidence of doping or EPO or something.
That's all I can think of. Who cares if Floyd Landis and some medical experts testify against him? Like you said, if the testimony was that important, why test at all? The answer has to be that they have more than just the testimony. There must be some physical evidence or a career fighter, not old by any means, with decades left to defend his career, would still fight.
I don't believe for a second that he's just tired of the fight. The man is a born competitor. No way does he just walk away.
It's also galling in the extreme that Jan Ullrich would now be given Armstrong's titles. I will never forget The Look:
Lance Armstrong Alpe D'Huez - YouTube