1) Your anecdotal stories are just that, no more. You can't make a rational conclusion by generalizing the entire non-techie population to the experiences you witness w/ your family, friends, or a stranger in a store.
2) There are not enough Apple loving techies in the world to account for even the majority of iPad 3 & 4 sales to date.
3) it's a bit disingenuous to call retina screens "slightly more crisp" [emphasis added]. It's kind if like saying Miami is only slightly warmer than New York City in January. Retina iPads are 2x the dpi of non-Retina models. That's not a minor technical difference.
Yes, some people would rather save $100. But not all are non-techies. Others think $100 for a better screen is a worthy upgrade. Not all of them are techies.
My wife is the perfect slice of the general audience. If you even walk into an Apple store and sit by the genius bar for 10 minutes you'll see about 20 of her to 1 of me. I check out all my co-workers tech and most of my co-workers still rock the iPhone 4 or 4S. Not the 5 or 5S until they get the upgrade. They don't pay extra for the little things... they're happy with "just the phone" or "just the tablet".
The iPad 3 and 4 have been in the market for nearly 2+ years now. Of course they'll have good marketshare... why don't you look up the iPad 2 sales outright and compare over the last 3 years? Why is Apple still selling the iPad 2? As the article posted in Macrumors stated; it's because it still sells. Why does it still sell? Because people prefer the cheaper model, in general.
As for your #3... that is subjective. After the honeymoon phase from switch up from iPad 2 to 3rd Gen I personally regretted the upgrade as it was so unnecessary. It does NOT help when watching video and while I CAN see the difference it doesn't change anything for me when I read (web or books). I've since dropped down to the iPad Mini, A. for cost and B. I wanted the smaller/lighter tablet... the only iPad I skipped so far has been the iPad 4th Gen.
As for your comparison I'd say the difference is it's more like; is it more Sunny in California or Florida?
Yes, not all people who paid the extra 100 for the upgrade are techies. They're the ones who have the extra income to burn. Basic economics dictates though that there are far more non-wealthy people than there are wealthy. (1% ring a bell?) And with more of one group means more of the bargain hunters.
Think about it this way; What kind of car do you drive? Is it the car you've always wanted to have? Is slower and fuel saving and slow like a Prius or Fast and fuel guzzling like a Ferrari? Two totally different cars and yet I see more of the slower one on the road. Don't people want the power? It's the same with tablets/computers/anything... you get what suits your personal lifestyle and in this economical world there are more people thinking of their wallets than their need to look at something more clearly vs not looking at one at all.