Good imagining and guessing
The rim weights in my post are the manufacturers' figures, not a guess. Some 29er wheels and tyres are very similar weights to their 26" version but some aren't. Also, when you up the size while keeping the weight and materials almost the same, doesn't that suggest to you that a compromise is being made somewhere?
I know lots of people who absolutely love 29ers, ride them all day, do well in races on them, etc. etc. Bizarre how people then have to go a step further and say that they are the ultimate bike for off-road, handling, weight and strength isn't an issue, and all sorts of other questionable statements.