I'm slightly confused.
Can you compare a currency market cap in USD to a company valuation??
Who is "buying" a cryptocurrency....?
Can you compare a currency market cap in USD to a company valuation??
Who is "buying" a cryptocurrency....?
Eg: If a company has 200M shares, and someone pays $1/share during an investment round, the company (and the press) will mention that the funding was done at a $200M valuation.
The same logic is done to calculate crypto currency market cap. If there are 200M coins, and someone somewhere pays $1/coin, the market cap is reported at $200M. This is, however, the total value of all coins of that currency. Often, the person(s) or company that created a coin won't own most coins (unlike with company shares).
The currency can't "go out of business", as it's entire existence is a speculation. Anyone using a given currency speculates that it will be accepted tomorrow.
It probably also points to a large difference between a new blockchain _Currency_ and a token _Asset_. The latter often being a proxy for company shares in an ICO.
You can compare the market caps in a sense. A company with 1000 shares worth $10 each has the same market cap as a cryptocurrency with 1000 tokens worth $10 each. The $10 price is the highest price people are willing to buy the share/token at. In economic terms, they're quite equivalent?
That's where the similarities end. A token does not mean ownership. It doesn't mean a share of profits. Tokens do not necessarily have any rules about how many there will be.
More practically, a single person owning 100% of a cryptocurrency would likely reduce the value to zero. Owning 100% of a company, you can at least sell its assets.