Bosfan

They are not traitors because Cersei has no legitimacy, is a kinslayer and by murdering Tyrells in sept she broke feudal contract and deal with faith. If anybody who sits on Iron Throne could proclaim itself a ruler, then Moonboy could have became a king.

Lannister army is all destroyed, if I understood that, and Cersei should now obviously lose Euron support. Why is this conflict getting draged on?

I posted this in another thread, but seriously there is no way that Olenna wouldn't use all that gold to hire GC or Faceless Men already as weapons against Cersei. She is the last Tyrell in the show, there is no point in not going all in.