You may as well be asking if you could go back to VGA. It's clearly the future.
I have had a MacBook Air for 3 years now, and have tried many Retina MacBooks during that period.
Ever since I laid my eyes on a Retina screen, I knew I'll get one.
However I'm still using my MacBook Air and haven't crossed the line yet, I was waiting for a 4K compatible (60 Hz) 13" MacBook Pro, which is finally out. In the meantime I've tried the MacBook 12", and think I'll wait for the MacBook Pro redesign before pulling the trigger. (I'm hoping for a lighter 13" rMBP)
It's a big step ahead regarding text quality, which is very interesting when you read/write a lot of text and when you're a programmer. Contrast and saturation are also way better than on my MacBook Air.
I'm not that satisfied with web image quality though, most of the time a picture or video looks crispier on the Air's non Retina screen, which doesn't interpolate pixels to fit the big resolution.
All in all, Retina is not perfect yet and I can live without it, but I know that I'll make the switch for my next major purchase and will not look back after that.
My external screen will also have to be at least 4K, not to suffer the transition from crispiness to blurriness that goes with a Retina laptop/non Retina external monitor setup.