JMO: they may have been dumped before the huge wave of publicity surrounding the case. Nonreas
Lots of people go missing in London, and elsewhere
Home - Missing People
and most of them get no publicity beyond their local area. And even those which do, it's not usually a wave such as this.
IMO, the online me marketing skills of her friends and colleagues made an enormous difference.
The alleged offender was unlucky that this was a woman who was missed rapidly, was clearly out of character to be missing, and whose disappearance resonated so deeply. None of which could an offender have predicted when seeing a lone woman on the street