Basically, yes, but also not quite no. Market products offer you an initial baseline experience. Aftermarket products offer you an enhanced "better than the average" experience. Postmarket (or postconsumer) products are a de-growth mechanism by which you extend the life of your initial purchase beyond its planned obsolescence. There used to be a really great paper on creating circular economies that accounted for how in the reduce-reuse-recycle cycle our capitalist society has placed all emphasis on recycle when that's supposed to be the third order option behind reduce (consumption) and reuse (by extending the life of the products you already own) but I can't seem to find it anymore, but that paper was where the PostmarketOS name came from

Do you really think anyone would see the name "postmarketOS" and right away think this is a Linux distro for phones? Perhaps the "-OS" part gives it away that it's some kind of OS, but so are a lot of projects that end with "-OS".

For example: ReactOS, RedoxOS, ChibiOS, MicroOS, TempleOS. Can you really look at any of these names without knowing beforehand and tell what it is about?