Died in the sense of it's almost impossible to buy a machine that supports ExpressCard any more. Until fairly recently, one of the 17" Windows workstations did (I forget who), but a quick perusal of their spec pages shows that that's gone, too.
Of course, people are still using old ExpressCards, but they're becoming harder and harder to support. There are pieces of lab equipment that still require RS-232 serial ports, Centronics parallel ports or pre-NT Windows (98) (in rare cases some piece of lab equipment will still depend on something like an Apple ][ series computer). The folks using them have no choice but to keep the fusty old hardware going, by cannibalizing machines found on eBay, or to replace a perfectly good mass spectrometer or whatever it is...
Of course, people are still using old ExpressCards, but they're becoming harder and harder to support. There are pieces of lab equipment that still require RS-232 serial ports, Centronics parallel ports or pre-NT Windows (98) (in rare cases some piece of lab equipment will still depend on something like an Apple ][ series computer). The folks using them have no choice but to keep the fusty old hardware going, by cannibalizing machines found on eBay, or to replace a perfectly good mass spectrometer or whatever it is...