Yes, I lived on selling my art during the 1990s at several points. I found out how physical it is to sell art in person and that's why I no longer do it.
I probably would've earned more if I wasn't disabled, people do not buy art from someone who's sick, passing out, in pain and would rather be home in bed. They want to buy from a happy artist who's enjoying the process and completely focused on it, rather than just drug out and hoping the pain will go away.
Online, there are many ways of selling art from selling it yourself on gallery sites and blogs, to doing commissions, to using sites like ArtFire, eBay, Etsy and others to make it available. I'd say it's easier today for anyone to sell art than it was in the past because you're less dependent on living in a place with a thriving art market.