Snipped by me for focus.
At the risk of making sweeping generalisations, sounding very judgemental, and over-simplifying things, I think it comes down to one word ... class. I see that
Sundaaaay has already beaten me to it on this point (post #748) and added other plausible explanations. Esther had a very expensive education, got a degree from one of the world's top universities, and has been "living the dream" for the last 6 years. I mean, she even represented her country at rowing back in her early days!
There are dozens, possibly hundreds, of people who go missing in the UK every day, but very, very few of them will be Esther's equal either in their socio-economic status or in terms of their lifestyle opportunities / choices. Their disappearances don't generate newspaper sales or click-through ad revenue.