ANSWER: Amaral had less than 5 months to figure things out, was booted out soon after he made the McCanns arguidos, and was then replaced by a government puppet. The 'armchair detectives', who include former senior police officers, have by contrast had eight years and ten months to sift, search for, find and analyse a whole lot more evidence and try and work out what really happened to Madeleine McCann.
Armchair detectives only have access to SOME of the evidence/information available to SY and have to rely on statements translated by amateurs. They have no ability to interview or reinterview anyone connected to the case, have no means of accessing information which only the police can access - and the vast majority have no experience whatsoever in detective work. .
Any reasonably intelligent person can easily see how that
must put armchair detectives at a major disadvantage to professional detectives who do have ALL the available information to hand, who have professionally translated files, the ability to make background checks etc and to actually interview people in person if necessary. And who also have years of experience in detective work under their belts.
Anyone who thinks that armchair detectives are equally or even better placed to solve this case than the professional police officers of two countries is seriously deluding themselves IMO.