This fantasy that the US was atrociously and morally behind the curve on slavery seems to get repeated by Marxist types that love to promote slavery as a unique blemish on the US.

The US as a whole abolished slavery in 1865 (though some states abolished it decades earlier) and it isn't surprising that it might take a little longer in a country structured like the US as you either need to reach or force some kind of consensus which is easier to do in some countries than others.

Mexico - 1829

England - 1834

France - 1848

US - 1865

Brazil - 1888

Many other countries were still abolishing slavery well into the 1960s. Also important to note that, the years these laws were passed around the world doesn't mean slavery stopped instantly at that date. It was quite the norm that slavery continued after it was abolished, not only in the US, but globally. It may not have been realistic to truly end it abruptly for many reasons, so some transition period was necessary.

Also worth mentioning that the US had a relatively small per capita population of slaves compared to many other countries. During this same relevant time period the US was seeing huge amounts of immigration from Europe which dwarfed any sort of slave labor, an expanding rail network, the leveraging of deep water harbors for shipping thanks to wonderful geography and an energy boom. New York was an absolute powerhouse of shipping.

We did containerize some domestic shipping before the rest of the world, but transitioning to it fully took some time.

Many countries had innovators, but what did they do with their innovators? Many countries had labor (slave or not), but what did they do with their labor? You can keep asking a series of questions like this and tend to find that US adapted its use of resources better on average.