Where? Geography is important here. I'm guessing you mean the US, in which case it might be useful to define what you mean by middle class - European usage tends to be different.

Whichever middle class it is, I think it would be a stretch to say that it was created by industrialisation. Its numbers and prosperity certainly increased (though those at the bottom often fared worse during the early stages), but it was already an element of the social order.

For the majority, even basic food security has been a more recent innovation: famine persisted in parts of western Europe into the 19th century, in the former USSR into the 20th, elsewhere still later. But a marked rise in living standards spread through 19th-century Europe and the Americas. The US may have been first with its opportunities for expansion into new lands, but large-scale poverty survived, notably in periods of economic downturn.