You said "Nostalgia from people with spare income - this drives the size of the market" < I have to ask, is that really what you think?
I don't agree. All of this comes down to the popularity of Star Wars, it's common-sense to deduce that, it's all about popularity, I don't think your notion about nostalgia has anything to do with it (who on earth pays $40,000 for a DT vintage Obi-Wan MOC because they feel nostalgic? LOL. Luke DT MOC sells for $25,000).
And I don't need to mention just how popular Star Wars really is, do I? Popularity drives demand, and nostalgia is only one aspect of popularity. Now since we have demand, rarity of certain figurines will ensure high-price, vintage or modern, makes no difference, rarity remains the immutable constant behind price in any sphere of buy-&-sell! The balance of supply-&-demand is the sole driver behind price, trust me.
And with the modern TFA figures, demand is there because it's Star Wars, not Spiderman! FYI the TFA figurine I have is more than likely the only one, or possibly at the very most one of a only hundred, which means it's 'ultra-rare'. This figure also has another factory fault, where the letters "TM" are not printed beside his name at the bottom left of the card, whereas all the other TFA 3.75" figures have "TM" printed beside their name at the bottom left of the card, so there's two things on this figure pack making it special and rare.
I say again, the demand is there because Star Wars is 'popular', nothing to do with age-group from the 70's and quaint longings. It's about a collectors mentality and the must-have mentality of so many kids.
Yes, the prequels were a flop, but even they were still popular; TFA wasn't a flop, far from it, and is regarded by many old school fans (including myself who saw ANH in 1977 with my own eyes) as on-par with ANH, TFA in it's own right has equaled the all-time classic for viewing pleasure (not interested in getting into an argument about that).
TFA was extremely unique in that it had the main characters return after 40 years (no movie in history has ever managed to achieve that), plus awesome new characters were introduced, and the movie itself was a smash-hit worldwide, and it only has Avatar to usurp before it will be the highest grossing movie of all time, which utterly proves it's popularity. As soon as the home movie release hits stores, it's gonna surpass Avatar in the blink of an eye... TFA WAS, AND IS, HUGELY POPULAR! STAR WARS< demand for figurines, I don't think vintage has much say in the matter.
Then rarity of any figure comes into play, since the worlds population has nearly doubled since 1977, another factor ensuring a certain amount of rarity because Hasbro has not been keeping up with demand, not even close; in fact, they are under-supplying to a shocking degree, which ultimately is more good news, certain TFA figures are harder to find than the 1977 ones.