Economic freedom is literally what defines socialism and capitalism. Pure socialism is when you have a fully planned economy and pure capitalism is when you have a fully private economy. Obviously neither extreme works, but when you actually look at the data, you'll notice that there's a pretty strong correlation between freedom, prosperity, and happiness and economic freedom. The more economically free countries are the best performing ones.
Also the US is not the most capitalist country nor is it the standard of capitalism. There are plenty of other countries with that are just as, if not more capitalist. Even then, the US is still a very free, prosperous, and happy country. It is objectively very well developed and well performing, even if it isn't the best preforming capitalist country or liberal democracy. This idea that the US is the definition of capitalism or that the US is a "soon to be collapsed^TM^" third world country literally stems from Soviet propaganda (which was inherited by modern Russia and China).