In international shipping nearly all ships are standard designs and built at a relatively small number of shipyards, mainly in N.E.Asia. This is especially so for large tankers, bulker, LNG carriers and Container ships.
You are right, they are designed, built and equipped to the minimum required standard as set by IMO and Classification Societies, with some flag state setting slightly higher requirements than others.
There are also a few Shipping Companies that set their own standard a bit above the min. requirements, but far and away the largest number are Asset Players, not old fashion Shipowners, who cared about their ships and crews.
Whether you like to hear it or not, Scandinavians are among those who set higher standards, (Maersk among them) but there are also Scandinavians among the pure asset players, who care for nothing else than the bottom line. (I could name some)
In the offshore, short sea and specialized shipping there are still a few of the old fashion Shipowners, who have themselves been at sea. They know ships and care about their crews, but they are also bound by the need to make money for their share and bond holders.
I don’t know if there are any of that type in US shipping, except for small tug owners maybe??