maikeru: That is a very nice post and I agree with many of your points. And of course your last paragraph - I of course expect there to be tons of people that will defend Ayu on here, no matter what.
It is an Ayu board after all. But at the same time, there need to be at least some people who are willing to play devil's advocate or else there would be no meaningful discussion at all I don't think.
I do however strongly believe that her sales these days are driven by her fanclub and I think the reasons for that have been elaborated a lot elsewhere. About the concert tickets though: I think most Team Ayu members usually sign up for every date that is in their area just to see what they might get. (since you are not automatically guaranteed a ticket just because you are in the fanclub) So that means that yes, all dates shouldn't really have any problem selling out when you have people lotterying for as many tickets as possible. (and it is a good thing too for us foreign fans or else we wouldn't have the opportunity to get nearly as many tickets on the resale market. ^_^) And aside from that, I do think a lot of people, especially in the fanclub, see her more than once on the tour. After all, you've got the traveling caravan of Ayu vans and fans that go to almost every date.
But I think the fanbase thing applies more to her single sales lately than anything else and not quite as much to the concerts. (when you take into account such a large fanclub of 70,000 members) That is 70,000 of Sunrise/Sunsets sales right there assuming that nearly all fanclub members would buy 1 copy and that a portion of them would actually buy more than one. Now, when the day comes that she struggles to hit even 70,000 with her single sales, then that means its reallllly trouble time.