Sure, anyone can list ten features Photoshop has that GIMP, for example, lacks. But it's just as easy to list ten features GIMP has that Photoshop lacks. They're not trying to be the same program.

I see the same argument all the time about Windows vs Linux. Linux lacks this, Linux lacks that, etc... but somehow, people fail to notice that Windows lacks a whole lot of important things that Linux has. Because a Windows user won't be aware of what they're missing. But for me, coming from a Linux background, Windows is missing so much I would view it as unusable.

Changing from one to the other is painful, because of the differences. It's not a drop-in replacement you can keep using exactly the same way. But that doesn't make either one better or worse. They're different, and that's a good thing. But different requires learning, and learning is hard.

Anyway, you're correct that $FreeProgram isn't a drop-in replacement for $ProprietaryProgram. But that's not a valid argument on the relative value of the two programs.