I suspect there is more going here.
Haley might be holding on in some vain hope but I think it’s more than that.
The RNC is apparently fast tracking some internal rules before Trump becomes the nominee. Something to do with not covering his legal fees outside of anything involving his run for presidency.
RNC member floats draft resolutions to bar committee from paying Trump’s legal bills
A member of the Republican National Committee (RNC) floated two draft resolutions Saturday that would bar the committee from paying former President Trump’s mounting legal fees and ensure it …thehill.com
It could be that reason why she is staying on and being encouraged by some quarters to do so.
He's trying to position his daughter in law Lara Trump to become co-chair of the Republican National Committee. She's outright stated that her loyalty is to her father in law (versus the party or the country), and that she intends to use the RNC as a mechanism to fund his legal expenses. I could see the party establishment being concerned about a de facto dynastic takeover of one of their primary fundraising vehicles. I think we're going to see some serious infighting here.