[appease7727]

Lots of automation. Dicing is automatic, bonding, testing are automatic. The manual work is mostly just transporting materials.

The bonding machines are crazy. Definitely look it up on YouTube, the machine puts down bond wires super fast.

The other part of it is sheer scale. Once you start making thousands or millions of something, economies of scale drive the costs way down

[rwmj]

And for reference there's a section in this BBC film about how it was done in the 1970s, by hand: https://www.bbc.co.uk/programmes/p01z4rrj

[wildzzz]

Bond wires really are a thing of the past now except in niche applications or legacy chips. Flip chip designs have the die directly interface with a substrate that is then soldered to the board. With the kinds of speedy signals modern chips use, bond wires introduce impedance mismatch that degrades quality. This is related to why you don't see many new designs using pins.