I have a gold cup and while they are selling for 20-30 percent more than I paid for it, they are no where near the 3-4 times value you posted.
The last time I priced a new gold cup back in the 1980's you could get a Gold Cup for $400 to $425 retail all over Houston. Carter Country had them for $405 and they are not cheap on their prices. I certainly wish I had bought a dozen of them and put them in the safe. Recently, I have seen them in like new in the box condition bringing upwards of $1200. It is true they have not gone up as much as the older colt revolvers, but it is a lot more than 20 or 30 percent.
I will grant they are nothing like the Pythons in like new condition or the Diamond backs, as far as going up in multiples of their original cost. I bought a 22. LR Diamond back new for $285 in Pasadena Texas in the 1980's and sold it about 6 or 7 years ago for $1000 with box and papers. It was in excellent condition with a very low round count, but not quite like new. I expect it will bring well over $1200 today if it is still in that condition.
These early no rail 4513TSW were made 1997-1999, so the Colts I am referring to had longer to appreciate. That is one factor I did not allow for. I don't know what the newer Gold Cups were selling for in the same period (1997-99). So if you are looking at 1997-99 prices, and all I remember are the very early prices, you may be right and I may be comparing very different time frames. I really don't follow Colts as I don't intend to ever buy another one. I am simply reacting to some of the recent values that have been staggeringly high for what you get, and for what they sold for when I was pricing them.
In 1993 I bought new a 4006 (not the TSW) for $500. I still have the box and paperwork on it and I have put maybe 200 rounds through it. It was never carried and basically in pristine condition. If I were interested in selling it, which at this time I am not, I doubt I could get more than $600 to $650 for it 20 years later in vastly inflated dollars. in real value it is worth less today than when I bought it.
In other words my original payment of $500 would buy more than $1000 dollars of most items these days. Certainly my 1993 $500 would be worth more than a $1000 today in groceries, gas, automobiles, motor cycles, homes, and all the other items the government does not use when calculating inflation. So unlike my Colt diamond back that increased in value far above the rate of inflation, my third generation 4006 has actually lost value in terms of real buying power.
So getting back to the original theme of third generation pistols being over priced and selling for more than they originally costs, I say no way. I still think third generation pistols are one of the best value buys in firearms today. They are the only real high quality gun I can think of that is under priced in the market place today.
One reason for this is that 3 to 6 years ago, a great many police departments dumped all their third generation pistols on the market at the same time. This flooded the market and kept prices down for a long time. That over supply has slowly but surely been absorbed by the civilian population. Prices are starting to rise on third generation pistols, but nothing like I expect them to rise in the next 10 years.
I expect those complaining about current prices of third generation pistols are reacting to the increase from the prices of a few years ago when the market was artificially depressed and flooded by all the police service guns, as so many departments switched to the cheaper plastic fantastic pistols. The supply for several years exceeded the demand. That is no longer the case, so look for them to go up up up from here.