To which I say hold on there a second. Firstly you probably do own some treasuries. If you have any kind of pension it will have some treasuries in it. Also if you buy something like a stock etf they will hold their cash in treasuries probably or use treasuries as collateral when they need to do margin trades. Also your credit card, mortgage, car loan anything like that if you hold it is priced at a spread above treasuries. The spread is to take into account how much more risky you are than the US govt.
Also say you’re a founder and you’re doing some kind of investment round. Well the investors are going to price your business using a discounted cash flow model as part of their decision-making process. The discount is an interest rate that is calculated using treasuries. Basically you look at the future cash flows and you deduct interest that you could get on such an asset to get an idea of the value of that future cash today.
When someone wants to ship a containerload of goods and they accept a bill of trade or whatever that includes a counterparty credit spread which is a spread over treasuries. You heard a lot about the LIBOR scandal a few years back well interbank rates are derived from a credit curve that is bootstrapped using treasury rates. So any kind of cross-currency transaction or thing with fixed or floating interest (even if it’s not in dollars) is likely to be affected by US treasuries.
Literally every financial asset is tied in some way to treasuries because a “risk free rate” is at the basis of option pricing, discounting, lending and borrowing, margin, counterparty credit adjustment etc etc.