Well, nothing that I wrote is written in stone
What is "minor adjustment" or "minor improvement" is very subjective. For example, you get deal with high ISO noise way better if you use DNG. That may be classified as a minor improvement, though it can also be the one that saves the photo.
In general I agree with you. Probably in all circumstances it's better to shoot RAW, but the need of post-processing it creates sometimes makes you not want to do it and be happy with the JPEG version.
Of course, there are more benefits. Wider angle is one of my favorites. (In the example I posted I actually did some geometric corrections and cropping to make the framing a bit more similar to JPEG - I wanted to show the shadow detail than can be brought up. The actual RAW viewing angle is larger.) Yes, chromatic abberations can also be corrected, often to an amazing degree.
If one has the desire for editing, DNG provides maximum flexibility. I have many examples where I made some spectacual edits, but I only have edited DNGs so I can't post it for A/B comparison. After all, I only do such A/B comparisons for fun and don't spend too much time on it, and my best edits have no "B" to compare it with of course.
Since I've started editing DNGs, I don't even want to edit JPG anymore. For me JPEGs are for P&S occasions, while art is strictly for RAW shooting. It really irritates me to edit JPGs because anything you do makes an image look fake - it just lacks information because it's compressed. It's as simple as that. Even minor exposure adjustments in post reveal ugly shadow detail that was concealed while it was dark, or color posterization when you change the hilights etc - e.g. sky looking uniformly blue. Try changing white balance even a bit and some really strange hues start happening.
People often say that "JPEGs are for final product", and it indeed is so. Due to it's techical nature, it aims to reduce details that are deemed not visible. Editing photos in a way that exposes such detail or in general changes a photo in a significant way is something that should not be done to a JPG photo - it's an attempt to extract an info which isn't there and you get more visible artifacts instead.
You asked about a workflow people are using for RAW editing..
I use mainly Adobe Camera RAW. It's the same as Lightroom but I prefer the "condensed" look of ACR. I find it works better with my 15" laptop screen.
I often do "Content Aware Filling" (in Photoshop) of black areas on the edges of DNGs so I don't have to crop. Often it looks deceiving enough. So yeah, it 95% Adobe Camera RAW. I approach my photos as a whole and don't like to do a lot of local adjustments or some crazy Photoshop kung-fu
Example you've shown shows nicely what can be achieved, though an image looks a bit dark now for my taste.