As for people in power making the Khashoggi case a big deal, that would be the Turkish government. They have many reasons for disliking the Saudi leadership, so many I won’t even try.
https://en.m.wikipedia.org/wiki/State-sponsored_terrorism#Sa...
The problem with the Saudis is they are very sloppy with their money, pretty incompetent and see certain forms if jihadism as legitimate. The incompetence means they often act counterproductively. Those are all problems and the western world needs to try to manage and limit the damage they cause. However hallucinating conspiracy crap on top of that just obscures the picture and makes tackling the real problems a lot more difficult.
[1] https://nypost.com/2017/09/09/saudi-government-allegedly-fun...
Saudis have long memories about this.
The only thing that made this different is that this time there were some people in power who decided to make it a big deal.