Of course there's a ruling class. Capitalist relations reproduce through production organized by class domination. What is the genesis and order of the rule of property if not class society? Who are these "managers and technicians"? I don't understand you.
The existence or non-existence of the bourgeoisie is, for me, largely a cultural question. Which is to say, bourgeois values and other cultural artifacts aren't particularly fundamental to capitalist production; the bourgeoisie is not a central component of the productive relations. Any specific ruling class isn't necessarily bourgeois. Management of these relations isn't beholden to a specific politico-cultural establishment because capitalism hollows out culture. It renders it superfluous because the primary object of capitalist society is not an object of a particular cultural entity but instead is a universaliz(ing)ed abstraction.
Maybe I'm being a dogmatic and self-righteous, but people who use this site really need to learn to unpack their categories and such. Not everyone knows what the "real domination of capital" means or its implications as a theoretical framework for a critique of social relations. You can't just assume people know what you're talking about when referencing very specific and elaborate theories. Its very annoying when people don't do this. (And if I'm guilty of this, I apologize.) This is a Q&A site—the compression of the terms and ideas implicated in any inquiry is not helpful to the resultant discussion.
From Marxists Internet Archive, Glossary:
"Subsumption, Formal and Real
Subsumption is the process by which the social relations of production penetrate the labour process itself. Marx distinguishes between the ‘formal’ and ‘real’ subsumption of the labour process by capital.
This concept is central to how Marx conceives of how capitalism establishes itself. In the chapter in Capital on ‘Primitive Accumulation’ Marx showed that genuinely capitalist accumulation could only take place on the basis of productive forces and social relations which themselves could only arise on the basis of capital. At first, capital draws into itself an existing labour process – techniques, markets, means of production and workers. This Marx calls ‘formal’ subsumption, under which the whole labour process continues much as before, but by monopolising the means of production, and therefore the workers’ means of subsistence, the capitalist compels the worker to submit to the wage-labour, and by using the existing markets, is able to accumulate capital.
Capitalism as such, however, cannot develop on the limited basis it finds in the already existing forces of production. The pre-requisites for a real capitalist labour process can only be created by capital itself. Thus, capital gradually transforms the social relations and modes of labour until they become thoroughly imbued with the nature and requirements of capital, and the labour process is really subsumed under capital. This is Marx’s solution to the paradox that only capital can create the conditions for capitalist production."
"But do they truly rule?"
Go out and violate property laws. Or better yet, participate in a prolonged workplace sabotage. You'll find out soon enough.
"Those who are at the top of the ziggurat of capitalism exist totally within social structures and discourses, and are coded by them."
I wasn't aware there was a definitive model of human society that isn't ordered through "social structures and discourses", and that inhabitants of it aren't "coded by them". Yes, capitalist relations, and specifically its pursuit of pure abstraction, leaves quite the impression on even those who command the means of acquiring that abstraction, that "Value". How does this imply the negation of class rule?