The weird thing is, they don't actually sell the jars anymore. "Ball jars" are not made by the ball jar corporation after their antitrust lawsuits for being a fucking jar monopoly. So they sold the "ball jar" rights and now only do aluminum cans for food packaging and high end satellites and satellite launch systems.
On December 11, 1939, the U.S. Government sued the Ball
Brothers, the Hazel-Atlas Glass Co., and the Owens-Illinois Glass Co. under monopoly charges
based on the Hartford-Empire and Owens licensing agreements. The plaintiff claimed that small
producers were being frozen out of business or prohibited from entering manufacture by the
nature of the licenses.
Almost a decade later, in 1947, the justices rendered a final verdict. The court prohibited
the Ball Brothers from purchasing or otherwise controlling any other businesses engaged in the
same manufacturing processes – in other words, the small jar producers. In addition, Ball had to
divest itself of the Three Rivers Glass Co. (already closed for almost a decade) that Ball had
acquired in 1936. Ball sold the property
So, at the time (1930) ball jar actually would have qualified as big business in the sense that you mean.
Home canning was very popular and they consistently bought out smaller companies.
Since they were privately owned, it's tricky to find specifics about value, but they were "found a university", "own a company town or two", "chairman of the federal reserve" levels of rich.