Earlier quoted context omitted.
First, I fully agree: this is not a bug, it's a missing feature. Second, I may be a minority here, but I actually don't mind this feature missing at all. I however do (or did) mind Windows putting its "thumbs.db" files all over the place, so that's the first thing I deactivate when installing it (along with enabling "show hidden files" and "show extension for known file types").
- "Welcome to the new GNOME car. It's totally free!". - "Looks great. But there are no mirrors. Isn't that dangerous?" - "Yeah, but that's not a bug, it's a missing feature. Besides, we don't like mirrors because in all cars they need to be cleaned all the time." - "Really? Apparently the KDE cars also have mirrors but different technology, and they don't need to be cleaned at all. Also, what's the difference between…
I'm not saying that it's not a nice feature to have, but it's also definitely non-trivial - it's not only thumbnails for images, if you do that people will also demand thumbnails for videos (including, of course, all ancient formats), PDF files, Word/Excel/PowerPoint documents, HTML pages etc. etc. etc.