Cause JJs failure could sorta turn into Rians victory.
Since TROS is sucking even harder BOwise, Disney might be tempted to think: TLJ was critically acclaimed; Tros wasn't -- Rian is not the problem but Rey, Finn, First Order the whole setting. People don't hate him directly (i think they do lul), they just hate everything ST.
And KK always seemed satisfied with Rians overall approach anyway... Or at least she harassed him considerably less than others.