Not everyone who does light image editing as part of their professional setting needs professional tools straight away. The mental overhead of having to manage software installation, licensing, etc. is just not worth it, even if you're willing to spend the extra $300 per year for it.

And as mentioned, Affinity/Adobe software is not available on Linux, which immediately disqualifies it for me personally, even though I'd like to upgrade past GIMP and I'm very much used to Photoshop after years of using it.