Well, it was an example, but our technology such as laptops seems to sell cheaper second hand, same with articles of clothing or furniture.

I believe it stems from a tradition of not disposing of things, and instead selling them on (via "car boot" sales) or handing them down. I believe (and this is pure conjecture) that it's a recent thing for brits to dispose of things with such frivolity, and this is somewhat echoed in the car-boot sales of late being chock-full of brand new mostly chinese cheap crap.

And maybe if you have an overabundance of second-hand goods then maybe the price goes down as all of the friction to sell even things considered "tat" are gone.

And most of the things we would consider "tat" are not "tat" to everyone else, for instance, I bought my first computers for 5gbp from a boot-sale, for such a token amount of money it is likely a person would not have sold it another way. Thus, I get a cheaper computer than I would have had to pay otherwise.