don't think 26" wheels are a foot in the grave
just a the law of economics and marketing impacts
we see this all the time in cars, electronics, etc
the marketing engines will soon slow and a winner will prevail btwn the 27.5 and 29
I have a few 26", one 29 but no 27.5, one 26" has really chunky tires making it close to a 27.5
I'm not particularly tall so the 29 doesn't work for all applications, but in the right conditions, the 29er is sweet