Insurance minimums for something like a cessna 340 are extremely high. A customer at our flight school purchased one, spent a ton of money on the avionics, and ended up with a really nice aircraft. He needed to log 150 hours dual in it, as well as going to a systems course like flight safety offers. I can't even begin to imagine what the VLJ insurance mins are going to be like.
Also, there are already a number of single-pilot aircraft out there that already fill this mission. CJ's, the Raytheon Premere, and I would even argue that a King Air 200 can be considered (range alone makes it faster than some of these VLJs in a long flight). In four years fueling at an FBO I have rarely seen any of these aircraft without two people in the front. It's often cheaper to pay some timebuilder 30k per year than it is to insure for single pilot ops.