London (like much of Western Europe) was heavily demolished during WWII, so had to rebuild.

While during the same period the US was the opposite - it had an explosion of manufacturing growth during WWII, and having it dispersed made sense in numerous ways - it’s where the population was, or where space was available to easily expand, or where certain resources were, or even was far enough away from population for safety reasons (see uranium enrichment at Rocky Flats northwest of Denver, which is now largely an open space because you simply can’t reclaim that soil with all the uranium dust buried in it). You can see this in many cities where the old industrial areas are being reclaimed and converted to housing, shopping, entertainment, etc.

So you have 19th century engineering used during massive manufacturing growth ((because it was established and many older engineers (beyond draft age) had years of experience with it) in the US, while Europe saw destruction of lots of 19th century (and earlier) development.

Rebuilding happened during the mid-20th. So why wouldn’t you use the newest engineering.

In the US I once worked at a company manufacturing leather belts for factories that still had drive shafts running equipment. They were also using lathes from WWII, because it was precise enough for the assembly line machinery which was similar in age. Upgrading would cost more than it was worth (this was in the early 2000’s). I suspect their entire plant was built during WWII.

One way to look at it - in land space, the US is equivalent to 16 western OECD countries. Comparing a single European country to the US is meaningless. Better to compare most of the EU, and even then historical events, and political borders make for very different results.