Fascism-as-theory does not necessarily correspond exactly to fascism in practice. In the real world, the most likely (if not the only possible) manner in which State and Corporation can come to merge with each other is for strongly established corporate entities to become incrasingly involved in government.

And of course these powerful entities support "laissez-faire" policies only when they coincide with their own interests; when there are government incentives, tax-breaks, exceptions to regulation, etc., to be had, they'll grab 'em every time.

Speaking of theory-vs-practice, consider the vast difference between communism in theory and in practice. In theory, the workers rise up and take over (dictatorial) control of the "means of production" and, thereby, of their own lives. In practice, whoever assumes those dictatorial powers immediately ceases to be a noble and humble worker, becoming exactly the kind of self-interested tyrant who ran the previous regime.