That's an appropriate use of was. The US hasn't been a Capitalist nation in nearly a century.

It's a heavily regulated mixed economic system. That transition largely occurred from roughly 1930 to 1980, and the tsunami of unnecessary regulations have continued to rapidly pile up by the thousands ever since.

Free market? Ha. Sweden is more of a free market than the US. The US has a very large market with some free market remnants; the big economic outcomes that enables is what confuses people into thinking the US is still a bastion of Capitalism (while it rapidly speeds toward the French model of economic stagnation with persistently falling growth rates).