With increasing size of corporations (which buyout competition to create market monopolies) the market economy is turning into a centralized economy, isn't it?

With increasing size of corporations (which buyout competition to create market monopolies) the market economy is turning into a centralized economy, isn't it? Just instead of an entity called "political party" it's being directed by board of directors of said corporations. And they're very effective at lobbying further to decrease chances of market competition as well. So the system you're describing is not actually happening to the extent we need in the wild, we're drifting away from market economies to centralized economies.