Big tankers doing long voyages will still be using tugs for berthing and unberthing, likewise the ULOC and other such big monsters.
Even the large Mega Container ships are likely to get enough thruster power in the bow to manage with one tug aft. When they become autonomous propulsion will probably be by Azipods/Azipull, or whatever became the next big thing, thus not require any tugs under normal circumstances.
PS> The Bow thruster Frequency Converter may also be used as shore power connection in ports where that is available/mandatory.
Port Authorities that try to force vessels to accept services they don’t need or want, will find that their port will loose traffic.
Likewise ports where Stevedores refuse to adjust to times will find that nobody comes. This happened in the UK in the 1960/70’s and to some ports in Australia when the Union bosses that had killed Liverpool and other ports in the UK migrated there.
One such port was Port Alma. Qld. In 1968 we arrived with a load of sawn timbers from the island and it took 4 days to discharge a 1400 DWT ship. Returning with a similar load in 1970 it was done in a day and a half. I was wondering what had changed and was told that the reefer ships had stopped calling because of their slow work. They insisted that any meat for export was transported to Gladstone or even Brisbane for loading there.