While I absolutely agree with what you are trying to say and donate to kde myself already. The issue with a lot of comments like yours is that the examples you use are almost always commercial software that already only see's limited use. I get value out of non commerical use applications such as dolphin, kate, konsole, and kdeconnect. Finding examples of popular paid versions of those applications would go a long way in my opinion because it would be something that more people can relate to.

The problem I see with the examples you are giving are the same problems I see when someone uses those examples as reasons why they can't switch to linux in the first place. And that is the fact that while those programs are popular. They aren't used by the vast majority of people who don't have a work related need to use them. Half the people that claim it as an excuse probably don't actually use those programs as well.

Your examples such as Cyberduc, Elmedia, and BBBedit are your stronger examples. Again just my opinion.

The Duck applications are all pretty nice.

They make more apps than just Cyberduck?