It’s also half the price of the D-Live/Avantis 64 channel Dante card. There are lots of reasons. Different channel counts. Technology changes. Some manufacturers make their own chips.
1: NY64-D is strictly 48khz vs the A&H card 48K + 96K
2: The A&H has src (Sample Rate Converter) allowing you to run 48K on the Dante network, while still run 96K internal in the console (wivh btw the console always do, regardless og external connections)
These two points require a higher standard of components after all.
I disagree. The first response to your question was accurate. The A&H SQ Dante card is twice as expensive as the Yamaha NY64-D card because in part, it is twice as powerful. Normal Dante chips will half the I/O count when you increase the clock speed from 48k to 96k. The Allen & Heath card does not do this. You can get the full 64 I/O channel count even running at 96k. The Yamaha card cannot do this, and most other non A&H Dante products can’t either. This is because A&H has designed their Dante cards themselves and don’t use the standard Audinate chips in their products, ensuring the get full channel I/O capabilities even running at 96k.