You are being pedantic. Things exist sometimes before they are called something. Capitalism existed before Adam Smith and he didn't even give it a name, that was given later. State capitalism is basically government support for key private industries through subsidies, tax breaks and the like and THAT happened long before it was called anything.
There's more to it than that.
By the standards you've given the current US government qualifies as state capitalist. After all it gives massive subsidies to the oil and agricultural industries, tax breaks to the banks and the wealthy, and a slew of other such policies and decisions.
State capitalism is more than just preferential government treatment to specific industries, fields, or companies. It's an approach to political economy where leaders in business and leaders in politics actively work together to shape national policy in a fashion that advances the perceived national interest. Germany pre-WWI arguably was that, Japan under the zaibatsus and the Meiji Restoration most definitely fit the bill, and later under Deng Xiaoping you can say China fits solidly.
What do each of those countries have in common?
Neighboring, industrialized competition and relatively underdeveloped economies coupled with a perceived need to massively overhaul industry to catch up.
If the South wins the Civil War by Fabian defense in 1864 there's nothing in that experience that would validate such a thesis.
There is no question during the Civil War that the North has vastly superior industrial resources. Yet clearly a Fabian defense in 1864 would invalidate the power that has by showing even in spite of superior industry they couldn't beat the South. The only other possible motivators for that kind of close intermingling of commercial and political interests would be if there's some other faction involved that's seen as a great industrial threat but a CSA winning alone by wearing out the Union doesn't have that. By 1864 the blockade had choked off CS trade so it can't be due to balance of payments or trade or something like that. Canada is largely forest and tundra with Britain, who with the blockade would not be seen as a decisive factor, an ocean away and far less relevant than the South.
If any economic lesson is learned its that agrarian countries are far more resilient to invasion than they appear to be and industrial production is not militarily decisive. A successful Fabian defense would partially vindicate the whole notion that a nation of shopkeepers and craftsmen can't beat a nation of farmers and hunters.
So why would policy-makers at the top of the business and political worlds decide the best strategy is to work hand in glove and turn the US into an industrial giant? There is literally none of the impetus that pushed Meiji Japan or Deng-era China to seek such a strategy and a lot of countervailing pieces of data suggesting something to the contrary. Furthermore there is nothing in the American political experience to suggest such an alliance or any kind of corporate/business organizations capable of operating on the scale necessary to make that possible outside of the railroads. Everything in the American experience suggests several things opposing the concept of such close federal cooperation with business.
True, but the ACW was a huge event in the US and its loss would change its future history drastically. The basic idea is that the United States would do everything in its power to prevent another secession movement. Encouraging very strong economic ties between states would go a long way in doing that.
The South and the North already had very strong economic ties binding the two together. The Northern industrial revolution would have been impossible without the cotton, jasmine, and rice of the South grown for both export and use in domestic markets.