Sea routes are God gifted and are cheaper. Countries have to build infrastructures like Sea Ports and ships to make the system functional. But, these things will become limited in the future to cross Atlantic or Pacific.
Now, soon it will be Asian era of development and so, nearby countries are building new infrastructures like highways and rail roads. Why? Because it is cheaper to transport goods on the land between nearby countries.
However, Sea routes will not close down. They will be operative. But, the land transport is cheaper in most cases because goods are not all produced near the Ports like Bombay. Sea route is 100% efficient in island countries like Japan. Even then it has built almost a million kms of highways and rail roads for internal transport.
India regularly begs BD to give connections for its transport to the NE. BD has already given a few. The Asian Highway route also goes from Kolkata to NE via BD. So, what is your point of argument?