In addition, you have couple of major risks such as feds making it illegal or taxing it heavily or some other coin that Elon Musk starts preaching heavily. At this point, if you do have BTC, you should sell out at $70K-100K range just to be safe. If you keep holding after that then you are taking increasingly bigger risks but much less reward.
The trick of bitcoin is that creates the illusion of value in its price in dollar (or other fiat) terms. There is no true underlying value. Note: bitcoin depends on the dollar because there is no independent bitcoin economy. So the price is simply what fools are willing to pay for it recently, what the last bid was. How much money has gone into the bitcoin black hole over time has almost no bearing on its price at any given instance besides hysteresis (i.e. the current instant price is near the last price).
Price is thus simply the dollar amount that people are willing to pay in the present moment for a bitcoin; there is no reason it could not go to $1,000,000 a coin if people are dumb enough to pay that amount.
This is why bitcoin is like a black hole. It is not an equity, since there is no underlying, fungible asset, i.e. ASIC miners can't be used for general purpose computation, bitcoin is not a share of ownership in anything, etc. The market cap of bitcoin is zero at all times regardless the price. The price provides an illusion of market cap or value but is not actually value in of itself. It exerts a pull on real money that can be used to fund productive or legal investment, like a black hole, but pouring money into Bitcoin does not give it value. Money can be destroyed, just like matter into a black hole and this is something cryptoholders will find out when (1) there is no greater fool left or (2) bitcoin soaks up so much real money that it has real economic effects, e.g. deflation, which results in a regulatory social clampdown or (3) there is a regulatory clamp down before that point due to recognition of bitcoins only real use case, illegal activities.
Dividing the total market cap by the total number of BTC relies on an incorrect assumption that BTC are never destroyed. But, in fact, we know that plenty of people have lost BTC keys. It's totally possible that the practical supply of BTC is far lower (e.g. 10%) than the supply of BTC on paper. In an extreme case (e.g. if less than 1% of BTC are actually usable), the paper market cap of BTC could exceed the size of the US economy, even while the true market cap is less than 5% (using your number).
For those who want a low effort fairly safe hedge against inflation and currency changes an index tracker fund is probably the way to go.
A small percentage on risky investments is probably fine, but then you do have to choose the correct risky ones =)
I wish I had bought Tesla shares in 2011 too.
I have had this conversation with many a friend, who actually view Bitcoin as a Ponzi, and therefore decide not to play the game (a ponzi ca be lucrative if : a) you know it's a ponzi b) you're smart in your timing and not too greedy but it's still a crapshoot).
The real questions are: