I've read that the 1-wire pullup resistor is included so that either the master or the slave device can pull the line low in order to communicate. Makes perfect sense: if the device had a transistor output stage pulling it high, then no other device would be able to commandeer the bus.
Most hobbyists seem to use the same resistor value. I have a suspicion this is not appropriate and that cable run is a factor here.
So, why is this critical resistor, which is always the same value for a given device, not integral to the device?