On the obvious flaw, even if you don't credit Gammons' report that the Bailey deal + $1 gets it done, it was clear from Lester's public comments that he would have signed at a significant discount. It's also just how this market operates -- if you're signing a year before FA, you're giving up the ability to test the waters and let the market decide in exchange for certainty. I don't think our not knowing exactly how much they're overpaying precludes discussion of the fact that they're overpaying.
On the much more important flaw, it's important, but it's not that important. The Red Sox (and apparently 6 other teams) want to sign him, not because of what he did in 2014, but because of what he's done over his career. Nothing about Jon Lester has fundamentally changed over the past season. He had a great year, the best of his career; this does not mean that he will continue to pitch at this level, or even effectively, going forward. He didn't get injured; this does not mean that he will not get injured going forward. There is some value in not being on the hook for nine figures if things had gone badly during 2014, but when you're considering whether to sign a long-term contract anyway, getting a one-year option (or IOW, a 'one-fifth to one-seventh of the total contract' option) is an extremely limited benefit.
More convincing is the change in the Red Sox own circumstances since ST; things fell apart. Buchholz Buchholz'd, Doubront imploded, none of the kids established themselves, and Lackey and Peavy are gone (the team's decision, but still). So yeah, it'd be fair to argue that Jon Lester (or any available frontline SP) is a bit more valuable to the Red Sox right now than back when they had an actual pitching rotation. Even so, in a best case scenario for the rotation, would they not be interested in resigning Lester? I think they try to retain him even if Buchholz had put up 30+ good starts and a couple of the kids had shown promise; there just aren't that many pitchers of his quality (even excluding 2014) available, and none of the others are Jon Freaking Lester. And if they would have wanted to retain him either way, why wait and do it at market rates? I just don't think a one-year option to see if he breaks down completely is worth $30+ million, especially when they're still going to be tying him up for six+ years.