However, it once again largely depends on where you live. I live in a small nation, this means that availability of used parts is low and thus they often are more expensive (making any savings less attractive). In other nations, scamming can be culturally a lot more common. Local, direct to person sales are more reliable, I do agree with that. However, that is largely depends on where you live and it still doesn't remove possibility of scam happening. My friend was young and inexperienced. They agreed to meet. However, seller came with GPU in hand and started exchange. A lot of people, especially young people will lack social skills and common sense to walk out from such a deal. That is, even if they don't find that suspicious in a first place. I read in local market that a lot of people just use mail to deliver packages between each other, often pay first - deliver later. So, I don't think that you take into account what most people are and what is best course of action for them is. For you or me, I don't doubt that used market can be a very fruitful field.
That is literally my own life experience. My friend is dealing with IT tech support in major institution and doing tech repair on the sides and he tells me how it is. I know better than most people here what industry is like. Not to mention, that I pick computer parts for average people. This is what separates me from you. You talk only about how it is like for yourself (tech enthusiast). I'm actually dealing with average people and know better how they are like.
the size of a country has nothing to do with it .
i´m living in a very small country in europe and yet i never got scammed
(and most locals here who are selling anything on a second hand market would tell you all sorts of fairytales just to earn those 5 bucks more on a deal ,
but for a person with average intellect it is actually very easy to decypher these bad actors) ...
when it comes to lifespan of a graphics card it usually takes decades for it to die .
even the mining cards are still running and i´m not affraid of them either
(i deal with people who are transparent about it and they admit they used those cards for mining but it was done in a professional way)
(just recently i bought 1660 super which was used as a mining card for a few months -
the seller has like 100 of these cards on hand and he is selling them below the usual market price
i got one which i will later use in some build for 60 euro -
which is a pretty sweet deal for a card that can still do 1080p esports and is basically as fast as rtx 3050 in rasterization)
i build a gtx 5900 (2003 video card) based retro system not so long ago
(and yes i bought all the parts from second hand market , it was like putting together a jigsaw)
and just yesterday i road 25 miles to buy a 4770K / gtx 1650 4gb 2x8gb system in person (paid 80 bucks for the entire thing) -
and surprise it is running (and pretty good at that)
but i will still do a bit of tweaking and restoration and it will run even better
after i´m finished i will resell it or give it to the kids in my family .
basically all i´m saying is you don´t need to be too much tech-savvy even
you just need to use common sense and ask for advice from people who actually know their stuff .
but that would take you few hours or even days of actual research . and that is the problem - this generation wants everything in 5 seconds ...
(i don´t want to attack young people (crazy for me to say since i´m actually not that old myself being born in the late 80s)
but it is true they are generally more lazy and more susceptible to being scammed (but that´s largely their own fault) -
extensive use of social media just makes people dumber in all areas - then they are severely lacking in both life skills and social skills .
they need everything served on a golden platter kinda and yet they still act like they are the smart ones
(also personal experience based on interactions with gen-Z kids) ...
when i watch my dad fixing a car or building something on his own it is me who feels like a dumbass compared to his generation ...
but the thing is i can acknowledge his generation was/is much more skilled when it comes to repairing/building stuff ,
while most of todays kids have zero respect .
anyways I digressed :
this all comes down to the one simple fact:
nobody can help you if you are too lazy to even ask for an advice .
and people on forums such as this offer their expertise and knowledge for free ...
second hand market is fine as long as you are not lazy and oblivious to certain things .
not to mention learning a few life skills and actually doing some in person deals and interactions can help you in the long run .
(if you want to practice your communication skills just go to the bank (let them try to sell you insurance or some lease or something)
or just visit some local shop or a local market place
and have a bit of a back and forth exchange of wits with the salesman a couple of times)