What does "one-parting" mean? Searching the web yields a couple of forum threads but no definition or explanation whatsoever.
Profit?! Commodore 64!! Sirs I duly doff my cap in your general direction.
They are still selling C64 games, which are still being written.
One example of boxed-games shop: https://rgcd.bigcartel.com/category/commodore-64
A page of a C64 games producer on Itch: https://psytronik.itch.io/
If you can call selling maybe hundreds of copies of a game profitable then you clearly know your way around personal finance :)
Being of sound mind, I interpreted 'profit' rhetorically. And the information was added because it is a safe bet that it will be read by appreciative passers-bys.
The games are naturally small - there is after all, limited hardware on offer - and people are not expecting AAA studio quality graphics and audio, because they are impossible on the platform.
Let's suppose then that you are living somewhere where you can live comfortably off a couple of thousand dollars a month. There are many, many parts of the World like this. Many you can live quite well on just a few hundred dollars a month.
Now let's suppose you can build a game in 2 months, and it will sell over its lifetime - say, 5 years - a thousand copies. And each copy nets you $2. It doesn't take a genius to work out that this not a bad lifestyle business investment of time and effort.
I think these guys are going to do OK, depending on where in the World they are. Most people in the US and Europe are spending an order of magnitude just to survive than the rest of the World, and think the hot stuff is in the software that takes years to build with multiple rounds of VC funding - there are alternatives.