Donna Murphy is a single mother and a widow who takes a really active role in her daughter's life. She only accepts work that will allow her to be there for Darmia, who is a big focus on Donna's social media, and that also means she has to consider the money. That means picking work with minimal time commitment and maximum financial gain. In the last few years she has lost both her husband and her best girlfriend to cancer, while continuing to work. Clearly, her personal life is of greater importance to her than a demanding eight show a week schedule. I think we should admire all her choices.
As far as her work in Hello Dolly goes, it has been said that the producers of the show didn't want to steal any focus from Bette Midler and refused Donna Murphy any publicity, not allowing her to do interviews or even appear in any publicity photographs in costume. It's hard to sell out shows with no pr at all. And yet those who saw her in the play said she was extraordinary, even better than Bette Midler, for some people. It should be noted that two time Tony winner Bernadette Peters was also unable to sell out the show when she went in to it.
Being a good mother is more important than being a star and Donna Murphy is not the first famous actor to make that distinction.