I think the question of lost opportunities versus costs is the best thing to look at here. You could pay a receptionist like 50-60k a year but they have to bring in the work. Maybe the AI dumps a percentage over a real receptionist but they still bring in more than the mailbox. But there's a cost to the AI too.
But the real question you should also ask is what else can that human do for you that the AI can't because they have eyes and ears and hands?