Unfortunately, the writer fails to mention that in England of the time, there was the landed gentry (distant relatives of the crown), and the aristocracy (direct relatives of the crown) and royalty. There really wasn't a middle class as such, and social mobility was almost nil.
Marx' theory was about how to break this deadlock of the upper classes of the time in the UK. They did have a stranglehold over the economy.
But today's Marxists are little more than thieves. They complain that the wealthy have the same strangelhold over the economy, yet there is unlimited upward mobility for anyone willing to make the effort.
They want to make the state the ultimate unchecked capitalist. Doleing out slave rations to the ignorant masses. Ending up with that which they hate.
Marx' theories were muddled. You are right about the aristocracy, but they weren't capitalists in any sense. Their wealth came from owning land. Commoners owned the factories. But he appealed to the model people knew and so they just figured that the capitalists would end up replacing the gentry.
But Marx was wrong about just about everything.
Disagree. Nineteenth-century England was "a nation of shopkeepers". Tradesmen, artificers, chandlers, merchants big and small, freehold farmers, masters and mates, junior army officers, and a small professional class of doctors, divines ("passing rich on forty pounds a year" -- as per Oliver Goldsmith), attorneys, and engineers made up the middle classes.
Even Silas Marner could accumulate a little pile of gold sovereigns.