Open source software like Gimp and Linux are free and can be run on your $50 single board computer instead of paying $500 for a laptop that requires a $139 OS license and a $119 software license for Affinity.
While it's certainly nice that those options exist, they are also entirely unsuitable for any kind of professional work. I assume the target user you're thinking of is looking to do some occasional, light-weight editing. And even this user will be frustrated with the irritating UI and workflow of software like (and in particular) The Gimp.
For me, it's close to unusable — and I am someone whose first computer was a TI44/4A. I'm a die-hard terminal shell user. Even Adobe Illustrator didn't really click for me. The Affinity suite made immediate sense.
That value costs money. A parent poster posited someone for whom ~$100 was a lot of money. You speak of professional work. I don't think the intersection of these two groups exist. Casual users with no money can use krita gimp darktable and be reasonable satisfied. Demanding professionals even in poorer parts of the world can use the wages earned to easily pay $100.
