I think it took her the perfect time to notice the dishonest behavior of her relatives. . . and above all, she gave everyone around her the chance to feel the same way.
If she had chased them away immediately as she did in his previous life, they would still have the power to put dissension into it, pointing it out as a tyrant and not paying much attention to the needs of the house and the adoptive children.
Now everyone had the chance to try out how badly Lucretia and Valentino are, and especially the kids will think about it three times before they trust their poisonous words.