so some things here:
-This is super major and dramatic, when was the last time you heard of a country arresting basically the whole top brass of its intelligence service because of a botched opp?
-If you think Saudi Arabia wanted this, no --- they were trying to pretend nothing happened or it was something else entirely --- Turkey has been forcing the hand of both Saudi Arabia and the US, because it had the the Saudi consulate wired. That ammo has been leaked out at damaging points to increase Turkey's leverage.
-Saudi Arabia and its allies need something to show justice has been done - and now they have arrested 18 involved, and uh, bad things happen when you're arrested for Murder in the Kingdom.
-Likely, both Saudi Arabia and the USA have capitulated to Turkish demands on some things, and they'll be getting some wonderful parting gifts to shut up and keep the tape under wraps. If there are further leaks, then you know Turkey isn't happy.
And yes everyone knows it's BS because the Prince had to have known, but he'll claim deniability, blame the underlings who will likely be executed for this., Turkey gets concessions because the Saudi Intelligence was incompetent enough to allow their consulate to be bugged and to commit a murder there, and the US can claim justice was done in Saudi Arabia and the murderers were dealt with by the Saudi justice system.