implausible: don't they have an answering machine?!

It seems implausible to me that in a household as wealthy as this Emily has to get out of the bath to answer the phone. In fact, they probably have not only an answering machine but a personal answering service. I realize that the plot demands that she answer the phone herself, but surely that could have been gotten around in the script. And am I the only person who doesn't bother to get out of the bath or shower if the phone rings? If it's important, they'll call back. As Walter Matthau once said in another movie, "the telephone has no constitutional right to be answered."
In many other ways, on the other hand, I think this is actually a more interesting movie than the original Hitchcock version.

How did it come to this?