You're thinking of the household-name famous artists (so-called "fine artists"), but those were far from the only ones.

There used to be many thousands of itinerant portrait painters ("commercial artists"), maybe tens of thousands. These guys would travel from town to town banging out quick pictures of members of your family or local dignitaries or the new City Hall or whatever. They weren't bad artists (they had to be competent to earn a living), but neither were they Leonardos.

Think of the best artist in an average high school class. Back then, going into the portrait painting business would have been a valid career option for that guy (they were almost all guys).

Now, some of them later became famous artists, or became famous for other reasons (Samuel Morse, of Morse Code fame, earned his living as a portrait painter at one point), but they were basically just tradesmen.

All those guys lost their jobs almost immediately when photography appeared.

Even today, unless you're very unusual, I'd bet you have way more professional photographs than professional paintings in your home (weddings, graduations, baptisms/bar mitzvahs/analogues for other religions...)