The M1 Carbine is the standard by which all PDWs are measured.

[JASmith]

...They were used because nobody had the vision to make something better. That doesn't make them brilliant.

Or did the technology and then-current design practice keep a better design from appearing? For example, the the first patent for a turbojet was granted in 1930. The standard designs of the 1950s were quite different due to a lot of development effort.

The centrifugal-compression jet engine was all but obsolete by 1960 even though aircraft like the USAF T37 continued to fly with them for at least another 30 years. A bunch of us have 6kHz hearing impairment from being oin or near the the "Tweet" for too long.

In other words, 'brilliance" needs to be defined by the then-current environment rather than the technology standards 90 years later.