No. I may have a wildly different perspective because I also have my feet dipped in the pool of board game development and tabletop miniatures. In that area, the line between the hobbyist and the professional is exactly as I describe. "Making money" is an unclear misnomer in deciding in which camp you fall into. A hobbyist is making something they are passionate (the ugliest word in the industry) about and hoping that someone likes it enough to pay them. A professional is tailoring a product for a market. In tabletop miniatures, for example, hobbyists are people who sculpt or paint minis in ways that they want, without any distinct or expressed consideration for the end user. They're doing it for themselves, first and foremost, because they love doing it. A professional is either looking at the market themselves and determining an under-served audience and targeting them with a specific product OR taking orders for a specific product type from a major publishing house or distributor with the expressed goal of marketing and selling their product to that target audience.
It's a difference of purpose and mindset, not a magical threshold you cross once someone buys the thing you made.
In my opinion.
By your definition then, where would you put devs like Vlambeer for example? It seems to me that these kinds of successful indies fall between your definition of hobyist and professional.