I'm hardly a big defender of SoI, and I mostly agree with you that people were never particularly likely to connect with SoI in the way that U2 would love.
However, I do think that the Apple debacle probably turned some people off from taking the album seriously, and the lack of a US promo tour somewhat dented U2's only hope at turning things around a bit. Not making the whole world connect with the album, but with making a non-negligible number of people interested in the album.
I agree that the release method probably turned off some people, I just don't think it "killed " the record. In other words, I don't believe a lot of people rejected U2 and their music solely because the release method turned them off. I think too much was made of that. I just don't think most people (meaning, not U2 fans) responded to the music, nor do I think the music really entered into the cultural zeitgeist the band always wants their music to. The record certainly did, but not because of the music. Of course, this is just my general sense, and I don't have any "proof" other than observing pop culture to back it up. Just my opinion.
This debate on whether the iTunes thing hurt or helped SOI has been going on here since the week it was released, and I've sort of gone back and forth on it. The argument I heard most was "no publicity is bad publicity", but I'm really staring to think that in this case that isn't really true. I used to think that U2 just wanted people to be talking about them and be "relevant"...but I'm not sure this did what they wanted. If ALL they wanted was to not be ignored (which is what I think they were afraid of) they certainly accomplished that. If they wanted to be loved and relevant again...no, I don't think so. Not relevant for the music they made, anyway.
If U2 had just released this record the traditional way, it would have made a splash to some degree since it was a U2 record. They would have sold a respectable number of copies, but probably not even as much as NLOTH (the band themselves have conceded this). Then it would have just sort of faded away.
So they did the iTunes thing, made a huge splash, got everyone talking about it, but the bulk of the buzz was negative. They really didn't sell many copies because they gave the thing away, and then it just sort of faded away.
So the end result in both scenarios is the same...the record itself never really did much, except in the latter case they had all the negative mocking to boot. I don't think most rock bands want to be in the position where they're being mocked. Hate is OK..but being mocked is not cool. Add to that that they really don't have any record sales to speak of, whereas a traditional release would have most likely at least moved a few million copies worldwide. Probably. Maybe. Financially for them I guess it's a wash and doesn't really matter, since the tour is where all the dollars, pounds and euros are anyway.
So it's hard to see the iTunes thing as nothing but a net negative...though perhaps a minor one, since the tour will do fine, which is really the point. And the tour will certainly get people talking about U2 again, the most likely in a positive way, but I don't think it will do much for the record.
And for anyone who thinks that SOI would have done better than the last record because they think the music's better, remember that every record since AYCLB has sold less than the previous one. So really, if you want to know how this record would have done had it been released the traditional way, all you have to do is look at NLOTH, then subtract.