Not to mention that Gilded Age business tycoons often treated their workers like shit because there were no legal restraints on them not to do so, and so many workers tried to organize labor unions to strike for better pay, working conditions, etc. And many of these strikes were violently opposed by the company owners and aided by the state and federal governments. Hundreds of workers were killed in violent strikes in that era - The National Railroad Strike of 1877, the Chicago Haymarket Square Riot, the Pullman Strike, the Homestead Strike, and so on. Ugly stuff, and it certainly wasn't a paradise for many, or even most, workers.
Also, instead of the capitalist idea of corporate competition, many companies formed monopolies which allowed for crappy products and high prices - farmers were routinely the victims of price gouging by railroad companies to move their products to market, for example. It may have been great for the wealthiest upper class, but it sure as hell wasn't all that great for the working class. But of course as we all know that's not who Trump is talking about - he's talking about himself and his buddies like Elon and that LA Times owner.