To do a 1:1 comparison with the cost of the superlift all you need is:
Front springs
Rear springs
Rancho 5000 rear shocks ($40 each?)
Better struts, better rear shocks and better UCAs are recommended additions to both but not required.
Add UCAs, struts and monotube shocks to the price of the superlift if you want a better comparison to the $1200 combination you priced out. Otherwise its misleading. The superlift is a better starting point, but is still lacking.
With the basic superlift you get:
1- to reuse stock front struts. ... they should be replaced
2- reuse stock UCAs.... they should also be replaced
3- basic twin tube shocks. ... they should be upgraded if you want to offroad
For your $1200 example you get
1- better replacement struts
2- stiffer springs for the front
3- upgraded replaced UCAs
4- quality monotube rear shocks
Hence there are other benefits. Add the necessary components to make up for the deficiencies in the standard superlift kit and you'll be closer to $2500, not $1600.