That reminds me of the people who say that LibreOffice is a complete substitute for MS Office, or that GIMP and Inkscape can replace Photoshop and Illustrator: they have no clue what professional use is, and that the open source apps don’t even begin to cover the specialized features professionals need.
Mighty strong generalizations there, tooki. Perhaps you might reconsider exactly what you claim about others there?
I must say, I take
serious umbrage at your claim that people like I have "no clue" – your emphasis – what professional use of such programs is.
I designed the first set of collectors cards for the Finnish Defence Forces in 1997, using Photoshop and Freehand. At the time, I was the webmaster there. Later, when running a company, I did some full stack web development stuff, and preferred Photoshop; and occasionally optimized artwork for use in official mailings etc, for which I typically used Adobe Illustrator.
I do not consider myself a graphic artist; I don't have the visual style needed for that stuff. I can do cards and icons, which don't need that much "artistry", and things that really interest me. I've had a couple of my oil pastels on display, but that's it; I could never do commissions or such. So, not an artist. I can definitely do the technical job, down to color separation, masks, and even custom rasterization if I need to. I've even taught a basic course on image processing (using Photoshop and Illustrator), although that was two decades ago. Most of my Photoshop work was taking proper artwork from a graphics artist, and optimize them for the task at hand (web, letterhead/watermarks, etc.).
All in all, I have a few years of professional Photoshop and Freehand/Illustrator use. I'm not much of an artist, only technically proficient.
Nowadays, I use GIMP and Inkscape. I can do everything I did in Illustrator and Photoshop, in GIMP and Inkscape, although the workflow is a bit different. For color separation and such, you do need additional (open source, possibly customized) tools.
Yes, the free tools lack spit and polish, and don't have the support and documentation behind them that Adobe can provide. Many common tasks are much more efficient with Photoshop and Illustrator, so anyone using them for their everyday workflow, definitely should consider using them. But if you only have GIMP and Inkscape, you can still achieve the exact same end results.
(Now, I really do have a bit of an esoteric career background... so, if you suspect I'm embellishing the details, do contact me via PM or email, and I can provide you with sufficient information for you to verify all of the above.)