Power of the Force through to just before Episode 1 was a crazy time for collecting. Those figures were hotter than hot and in hindsight many including myself neglected and even traded vintage to get these shiny new figures. Hasbro didnt release all the figures in the UK and the ones they did get were usually delayed, so this created a huge demand for grey market imports usually offered through Model and Collectors Mart. While £10 was an initial ballpark for an import, £15 and £20 soon became common as demand soared and never before offered figures such as Leia in Slave Outfit and Darth Vader with Removable helmet were produced. I have good memories of this time, much of it was based on nostalgia and the fact we had been so long without figures. Sure some of the sculpts were questionable and looked a but naff even at the time but as the range went on it improved a lot. I remember things were at a fever pitch just before Episode 1 and everyone was braced for Star Wars to burst through the stratosphere, then the movie hit, Hasbro got greedy and stuff just sat. For most of the noughties the volume of product and the amount on clearance seemed never ending and destroyed much of the collectability. Also the same figures kept getting redone over and over, so the novelty of stuff like the POTF Rebel Fleet Trooper, Slave Leia etc soon wore off as improved versions were produced.
Ironically a lot of the post Episode 3 stuff is now becoming pretty sought after, search prices for the Ulic Qel Droma and Exar Kun comic pack set for instance, but thats precisely because nearly everyone had given up by this point. I run a comics and collectables store and all my regular customers who religiously bought every figure had thrown in the towel by 2008.
I think all the modern Hasbro stuff still has legs, but demand will depend a lot on what Hasbro does with the brand and how the new movies continue to fare. Nineties toys are also starting to creep up slowly in value, ten years ago you couldnt get anything for stuff like the Kenner Aliens or Batman figures but now these are attracting fairly decent prices. Also most of the hoarders have long since got rid, there was a period when I used to roll my eyes when people came into my shop trying to sell POTF and Ep 1 stuff, but I hardly seen any of it these days and when you do see it the cards are usually wrecked. I would venture to suggest anyone trying to put together a set of POTF on mint cards might not find it as easy as they think. I dont think we'll ever see individual POTF in three figure sums but one day you may just claw back that £25 you spent on monkey faced Leia.