Pretty amazing I can sell my 1070s for over $100 and I paid $340 for them over 3 years ago.
Yeah but you need to understand gpus prices are not like used to be, gtx 1070 used to be sold for $349, now $499. Yeah, if you buy a 3070 today for $499 and then gpus prices increase once again to a 4070 $699 then yes you will have a resale value better than when you bought and that will hold but pay attention that $349 you paid in 2016 is today $499, inflation and other things. A good example is when you could buy a 3 bedroom house for 500 dollars some decades ago and today that money is worth a 3070 ehhe
Yep, that's the speed of money. A dollar today is worth 2 in the future. A bird in the hand is worth 2 in the bush, or something like that haha. Mining is a good hedge against all the crypto's value going to poop.
Getting $100 for a video after 4 years might sound great now until you consider in 4 years it's 1/2 of what it is right now. As always it's good to diversify - own different types of wealth (property, equities, rentals) and even in mining own nVidia and AMD cards in a mix.