Look at the reasons that trucks are used today instead of trains. The routes that trucks follow can change very quickly while it takes a long time to change railroad tracks. Even in the first days of railroads, it took a while to survey the proper route for a railroad. Truck roads can be built faster, they can go over rougher ground, they can go up and down grades that railroads can't. Schedules are much easier to change. At the start and end of the trip, trucks can change where they pick up and deliver to far easier than railroads can.
In Australia, they use trucks hauling many trailers as "truck trains". (Other places allow doubles and a few triples.) Again, this was faster than building a railroad.
We also have to look at the role of the government. The reason we got national railroads was due to the federal government deciding that such railroads were in the national interest and greatly subsidizing those railroads. The first national railroads received large amounts of land as pay and even today, much of the forest lands in some states still belong to the railroads. The federal government is still subsidizing railroads as it pays for rebuilding parts. Later on, our federal government decided to subsidize the highway system. The Interstate highway system is 90% paid for by the federal government. Even today, there are many voices stating that the taxes on cars are subsidizing the truck traffic as they say that truck taxes don't pay for the wear on the highways and bridges. There are major subsidies for the airline industry (airport, radar, air traffic control, etc.)
So, to answer your question, one of the major determinants of why very large truck would be used for logistics would be whether the government decided to subsidize the use of those trucks.