Those specs are not through Apple.com A cMBP 13" with a 128GB SSD and 8GB of RAM is $1,499. Only $200 less than the thinner, lighter, and 4X resolution rMBP 13". Your spec estimate is likely through OWC or something like that --- 95% of consumers will not send their brand new computer to some website called OWC and let them tear it open...void their warranty...and install aftermarket components. Glad it works for you, but that's just not a viable solution for most people.
1. The upgrades I mention most certainly aren't from Apple, as purchasing upgrades from Apple makes very little financial sense. Thus, the forced Apple-sourced "upgrades" in the rMBP-13 versus the base cMBP-13 make very little financial sense. Thus the rMBP-13 itself makes very little financial sense (which was my original point).
2. Upgrading hard drives and memory DOES NOT VOID THE WARRANTY.
3. The upgrades I mentioned would not require sending your computer anywhere. All can be done in less than an hour from the comfort of your living room couch and coffee table, by anyone who can hold a screwdriver and follow basic instructions which are all over the web (including on Apple's own website).