Let's pretend that in 1982, you purchased a thousand copies of ET The Extra Terrestrial for the Atari 2600. You would have spent about $40k doing so.

Let's pretend that you intend to sell them in 2018. They currently go for about $6. You're going to pay about a 30% overhead unloading them on the world, so you're going to make about $4k.

That $4k is not a capital gain. That $4k is a capital loss because you purchased the games for investment purposes and lost a shit ton of money. If you wish to get tax credit for those losses, tough titty. Doesn't work that way.

Let's instead pretend you bought 100 Lego Millennium Falcons for $800 (somehow) in September. Your investment is $80k. You're going to sell them after next september (which makes them long term rather than short term capital gains) for, oh, they seem to be about $3k right now. Minus your 30% ebay bullshit fee, you're going to clear $120k.

That $120k is a capital gain because the value of your capital... gained in value.

Capital is shit you own. If that shit loses value, it's a capital loss. If that shit gains value, it's a capital gain. If you profit off of it, you have made a capital gain.

Let's say your grandfather gave you eight copies of Superman number 1. One of those went for like $3m a while back; you're sitting on $24m in capital. However, you have not experienced a "capital gain" until you sell them. You would then pay capital gains tax, and then some. You also would have likely paid an inheritance tax when you received them. This is the sort of thing that makes Republicans mad: how dare you tax me for shit that I didn't work for!

Obviously, none of these circumstances have anything to do with your universe. Most of your stuff has lost value. The stuff that hasn't is a long way from $50k in capital gains. The "standard deduction" is what the IRS is willing to spot you precisely so you don't have to itemize and those receipts only come in handy if you itemize and if you get audited.

Capital gains is rich people problems. Those of us who liquidated $30k in Ethereum in order to buy Porsches might have to worry about it, but we're not and the standard deduction this year is half what it'll be next year. Chillax.