Prospects wary of one man shows?

I run the whole show and have no employees. So if something were to
happen to me, my business would end. Most prospects understand this
but a few express concern. What can I tell them to ease their fears? Can
I cite Microsoft and Bill Gates, i.e for most of Microsoft's initial
history, the company was run entirely by him? Or is that stretching
it since he always had people who could run the day to day operations.