When they were manufactured they were considered top of the line tools. Look at the size of the rings and today this is what you'd find on made in India bargain bin junk. The good old days were not that good. Nostalgia seldom agrees with the true reality of the times.
Most wrench manufacturers are used to using forging techniques to make wrenches between certain size ranges.
Once those size ranges get too small, or too large, the usual production methods don’t work well.
Wrenches this small are usually a bit crappy from many high quality manufacturers.
I think Snap-On, and one or more of the German manufacturers do a really nice job.
Maybe Facom, as well, and a one or more of the Japanese wrench manufacturers.
My older Armstrong wrenches were a bit crappy as far as manufacture.
The Craftsman wrenches in these sizes were way worse.
For wrenches in these sizes, machining the entire wrench, or cold forging would probably produce a significantly nicer wrench.