Why are airliner seats higher than chairs and couches at home?
The short answer, 

Your couch is made for you to fall asleep on, watch football from, and generally be of any non determinant shape since no couch (as far as I know) carries a type certificate. 

Aircraft seats are designed to fit as many passengers as is legally allowed and practically possible while still passing the 16G tests the FAA imposes. The 16G requirement is largely for your safety.

Most pilot seats are in some way adjustable up/down and forward/back depending on the age of your aircraft.