In 2004 Lance Armstrong sat in a press conference at the start of the Tour de France in the Belgian city of Liège, a week or so after the first serious allegations that he had used performance-enhancing drugs had appeared in the book LA Confidentiel, written by David Walsh and Pierre Ballester. Armstrong looked straight at Walsh, who was sitting in the front row and said: "Extraordinary allegations require extraordinary evidence." That settled the argument. For a while.

To Walsh and Ballester should go credit: they initiated the long, contorted process of revelation that has led the US Anti-Doping Agency (Usada) to hand Armstrong a lifetime ban and strip him of his seven Tour titles. The process had reached a watershed on Friday morning when Armstrong conceded that he did not wish to confront evidence that had been put together by Usada from accounts provided by 10 former team-mates which had led it to charge Armstrong with blood doping, the use of erythropoietin (EPO), testosterone and other substances, among other things. Had he conceded that the case should go to arbitration, he would have had to face those charges in a public forum. That evidence could have been "extraordinary": but Armstrong chose not to find out what it was. It is rare, possibly unprecedented, for Armstrong to withdraw from any combat. Fighting is his way, and always has been. But steering away from exposure of that evidence is the only outcome that permits Armstrong to maintain any semblance of control of proceedings, and to cling on to any scraps of the myth he has built around himself. But he does so with all the credibility of one of those fabled Japanese soldiers who hid on Pacific islands convinced that the second world war was still going on.

By avoiding having to give formal answers to the detailed allegations of his team-mates, he can continue to contend that the process was flawed, that Usada has indulged in a witch hunt, and he can state until he is blue in the face that he has never tested positive. (Back in 2000, at the start of a Tour de France stage, a close associate of the Texan told me emphatically that he would never, ever test positive. How right he was. But how pointless the notion.) Those arguments are now simply countered: if he has never used drugs, why did he not argue against the point in a formal setting? He has done that before, notably in the case against his insurers, SCA, and caused the opposition to settle.

It is strange now to contemplate the Armstrong journey. It is just under 20 years since I was introduced to a brash, extremely quick-witted Texan youth who had recently turned professional with the Motorola team. I liked him. And I was not alone. His great critic and eventual sworn enemy, the "troll in chief", Walsh, felt the same way when they first met in 1993. In 1997 and 1998 Armstrong could only be respected for the scale of the challenge he had taken on: returning from cancer to attempt to race again.

It is important to recall these things now, because we should remember that Armstrong has not always been what he has been since the early 2000s. He has not always been lawsuit-happy, was not always ready to browbeat those who raised their voices against him. If he goes down in cycling history as the biggest name to fall from grace among an entire generation that was tainted by drug-taking, that is partly because of the scale of what he achieved, partly because of the length of time during which he persisted in flying in the face of the evidence. Lance Armstrong's personal war is over now.

The sport should not be wringing its hands at this. The concession is sudden, the revelations anything but. It is not a case of "say it ain't so" but "say it, and let us move on". For the last eight years the weight of evidence against Armstrong has built inexorably: the two-year investigation by Walsh and Ballester that produced a book full of circumstantial evidence but no smoking gun; the positive tests for EPO uncovered in 2005 during research on samples from the 1999 Tour; most recently, the detailed account from his former team-mates, Tyler Hamilton and Floyd Landis, about doping practices at the Texan's US Postal Service. The Usada released a statement on Friday evening outlining the anti-doping rules that Armstrong had violated since 1998 as they justified the ban and removal of his titles. More details will emerge, and soon: to start with, Hamilton's account of his career and his doping will appear within a few weeks.

The discussion over the status of Armstrong's seven Tour de France victories is irrelevant. Other than their place in the records, those results ceased to have a great deal of meaning as long ago as 2006-7 once it became clear, from the Operación Puerto inquiry that an entire generation of cyclists, Armstrong's generation – Jan Ullrich, Ivan Basso, Alexandr Vinokourov and company – were tainted with blood doping. The Tour wins remained Armstrong's, but the standings beneath them became devoid of all sense. Now, the question of who the Tour wins should be awarded to would be an amusing party game were it not a grotesque illustration of a sport which completely lost its way in the early years of this century.

The Armstrong concession that he cannot win the case against Usada matters, because cycling can look, learn and move on. It already has moved on, in terms of how doping is discussed and the weight of opinion against it. Indeed, for several years now Armstrong has seemed like a man out of his time.

The tone of the time was shown in a lengthy interview by Armstrong's former team-mate Jonathan Vaughters this week in Bicycling magazine. Vaughters argued with great authority – authority born of experience at every end of the spectrum – why the fight against doping matters. To be deterred from doping, athletes need to feel – as Vaughters did – that they have more to lose from doping than they have to gain. Tests need to be strengthened, as they were in cycling after Armstrong quit for the first time in 2005.

By taking on Armstrong and pushing him to the point where he felt he would rather not contest the evidence, Travis Tygart and Usada have shown that no athlete can consider themselves immune from being pursued over doping allegations. As Bradley Wiggins argued recently in this paper, and David Millar has stated repeatedly in the past, to prevent doping, the temptation to dope needs to be countered in the athlete's mind with "why would I?" rather than "why wouldn't I?". In the sport's progress down that path, the Armstrong concession is indeed extraordinary.