Let's start with the fact Madeleine vanished then take it from there not with 'theories' but with EVIDENCE. Which is precisely what Wolters is doing at the moment. He has access to most of it enabling an informed opinion and you know nothing so like the rest you will have to wait.
You ask "how can anyone know what is correct?"don't you think trained police investigators are far more qualified than you to form opinions.
At the moment no-one except perhaps you is interested in rehashing Amaral's disastrous mistakes of 2007 - they are all far too busy waiting to see what Wolter's witnesses are saying in the here and now of 2021.
Yes, she vanished and no-one knows why. Abduction is a theory, whether you accept that or not. The trained Portuguese police investigators didn't find enough evidence to identify the crime. The Portuguese authorities made that plain when they archived the case in 2008.
Operation Grange seem to have decided Madeleine was abducted, but their reasons have never been made clear. We do have A C Rowley's comment, that she was too young to have gone off to start a new life, but no-one ever thought she had anyway. It seems like a very weak reason to assume abduction, but no doubt someone shared it with Wolters and he agreed.
I wonder if Wolters has found any witnesses who haven't shared their knowledge with the media?