Retina is not a big deal.
I can remember being a kid and switching from CGA to EGA:
What a difference! We went from purple a turquoise to 16 colors. The next big jump was going from EGA to VGA:
I begged my parents to sell our Tandy 1000 so we could buy a new 386 with a VGA monitor. VGA could display 256 colors (at 320 x 200). ATMachine has a great comparison between King's Quest V in EGA and VGA.
However, the biggest leap was going from VGA (320 x 200, 256 colors) to SVGA (800 x 600, and up to 16 million colors):
I've used two games from my childhood to illustrate the difference: Scorched Earth (on the left, VGA) and Worms (on the right, SVGA).
To me, all these jumps: CGA to EGA, EGA to VGA, VGA to SVGA felt significant.
I'm not sure if I'm just getting old, but the jump from "regular" iPhone, iPad, and Macbook resolutions to Retina doesn't feel as significant:
So I'm trying to decide if Retina is a big deal. Eventually, yes, I'll upgrade. But I don't have the same desire to upgrade as I did when I had an EGA video card, and I really wanted a VGA card. Likewise, I wonder if my kids would notice (or care) about the difference between a Retina and non-Retina display.