Another update - the Massport 2021 Annual Report includes this statement:

"In the fall of 2021, Massport completed the first phase of the Terminal B-to-C Roadway Improvements project by constructing dedicated arrival- and departure-level roadway connections from Terminal B to Terminal C for authorized bus vehicles only. When completed in late 2023, the Terminal B-to-C Roadway project will enhance safety by reducing traffic congestion between Boston Logan’s two busiest terminals, especially during peak travel times."

So, it looks like we are on the home stretch for "Logan Forward"