As mackey
posted in a HFC network the same signal goes to all subscribers so the electronics in a node is basically about transformation of an optical signal to electrical and vice versa.
In the case of ADSL or VDSL each subscriber gets their own link. That means line drivers/receivers are needed for each line, basically a DSL modem per line. All these signals need to be multiplexed/multiplexed over the backhaul connection.
If VDSL vectoring is used to cancel noise then complex DSP functionality is needed.
Lastly in some cases speed is increased by bonding two or more VDSL connections into a faster composite circuit. That also requires extra logic.
All in all a remote DSLAM is more complex than a HFC node.
/tom