I couldn’t watch much of that video but what was the answer? I had no idea people were buying retro stuff like that. Is the size for style and lifestyle signaling like the way hipster types used to have type writers and fixie bikes?
TLDR; there's only a few manufacturers making the underlying hardware as these are now niche low volume products. The engineering and manufacturing skill that went into producing Sony's smallest walkmen isn't particularly well reflected in the single design coming out of China right now.
It brings to mind Tom Hanks on SNL in the 90s as the Israeli shopkeeper saying his knockoff products all have 'Sony guts'.