Tbh, I have a feeling that Xebec was Betrayed by his "Entire Crew".
I mean sure, Xebec's Crew is different & Shiki explained it, but Oda didn't create a Single Character who is actually super Loyal to Xebec, regardless of their Power Level, Oda could have given him a Bogard or Rayleigh or Zoro or Beckman or Killer or Streusen or even a Bepo ... etc
Someone who feels like He is there to congratulate Xebec on his Success,
Imo the reason Oda didn't create such Character is because his Existence might have Spoiled such Plot Twist,
Especially when it's Suspicious how most of the 14 Confirmed Recruits so far are Confirmed to have Survived God's Valley,
And few who remain aren't Confirmed to have Died there,
When I say Betrayed, I don't mean They Attacked him, but I mean They Abandoned him, like Xebec was making a Crucial Move & He needed them to be in position, and They just left him,
He told them "I will show you what's on The Summit of The World",
Xebec's Mistake was thinking that his Crew would stick to the Plan once They witness whatever He discovered, He thought that as Pirates, They'd be as Loyal to Davy Jones as him (This is why He used Davy Back Fights to Recruit rather than straight out beat them up & forced them to Join, He wanted to Recruit only those who Honor Davy Jones Pirate Code),
What could They have seen?
Pirates who don't really care about Xebec but still would honor their Word suddenly decide that it's not wise to do so anymore,
What if these Pirates honor Pirate Code that is attributed to Davy Jones, but don't actually fully believe in his Myth, They just do it out of respect & honor, which means They don't actually believe that Davy Jones would claim their Soul if They don't honor the Games,
What happens if They suddenly found Proof that Everything about Davy Jones & his Threat is Real!
Do you know what this means? It means that if Xebec does become King of The World, then They will be forced to obey him forever, They wd no longer be able to decide to just go against him (Similar to how BB Pirates explained their Relationship), which also explains how Xebec intended to Rule & not fear his own Crew who are crazy strong turn against him, They simply cannot, it's too late.
God's Valley Incident isn't a Rocks Pirates Hype or WG Hype or Roger/Garp Hype, it's a wake up call to the Threat of "Davy Jones"!