Update: Still No Bueno !!
My new SIM card arrived today and I promptly installed it. That solved nothing at all. Also, it has become obvious that Stealthpanda's workaround is only a temporary fix ... until WiFi is turned on, or Airplane Mode, or ...
I called Verizon again, for the second time this week. They insist that they have not received any widespread reports of 4G data drops in Bionics. Maybe I'll go in to the local VZ store next week and demand a new phone!
Unhappy in Texas