Your logic is rich: Ruto worked hard on GEMA - thru mlolongo, mchangos and endless tours. But he has no solid grasp cause he is non-GEMA with a horror history of PEV. Being kicked out of Jubilee is as bad as BBI succeeding - because there is no "we are together with Uhuru" in a new URP. Without the Jubilee coalition he is basically back to URP - 20% - his real worth. Just as Raila ODM without the NASA coalition. Ruto presently hides behind Jubilee behemoth to create unbeatable facade. Very easy for Uhuru to scuttle that facade by choke-holding the party. This is live right now.
Ruto starts from a very bad place. Raila has used BBI to rally the majority of non-GEMA - which makes GEMA a must-win for Ruto. So these Jubilee "shadow-boxing" - is the ball is bouncing back n forth firmly in his danger zone. He has shed support in Mt Kenya - all Waigurus governors, senators and other Mt Kenya crème. Kiraitus, Kang'atas, Ephraims and Kagwes actually represent their folks - they are not suicidal or delusional. The Imenti will not leave Kiraitu and Munya for Ruto and Linturi - nor Tharaka leave Muthomi Njuki for Ruto and Kareke Mbiuki.
So it obvious just spin that GEMA will not leave Ruto - he only has them through Jubilee aka Uhuruto - which is going up in smoke as we watch.
I see no difference between Ruto today and Raila 2009-2017 - enemy of the state with a slim chance of success. You give him way too much unearned credit.
What would make half the mps go with Ruto? And half to remain with Raila? The thing is GEMA will not board Raila - they will board Uhuru or another GEMA if there was case to be made. But Uhuru is not going to manage to remove term limits.
Ruto right now can move with 90% of GEMA - but that is too early in the game. You cannot move because of Murathe or Tuju.
Ruto will only move when difference with Uhuru boils over publicly....not through proxies and shadowy characters....Uhuru has to come and say in black and white...he is joining ODM