Veloswap is tomorrow. I'll be there, FWIW.
The reason 29" bikes are better is mostly momentum and rolling inertia. You remember physics, right? The mass is farther away from the axle, so they tend to carry more energy than a 26" wheel. Harder to accelerate, too. Also the larger diameter means more contact patch, so that factors in. I don't personally think it's got to do with obstacles being spaced or sized on 26" wheels, but I dunno. There's so many different variables with bikes, less spinning on obstacles than trucks, so stuff isn't dug out on the climbs as much as washed out from erosion. I do think hardtail vs. suspension and wheelbase of the bike and where my fat butt is positioned relative to the front/rear makes a significant difference in how a bike handles. A 10mm longer stem or bumping the saddle back 10mm changes the handling quite a bit.
'91 Pickup - Imelda
'08 Tacoma TRD - Donna
'09 Kawasaki KLR650
'12 Gunnar Rockhound 29
"Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty. Nobody is able to achieve this completely, but the striving for such achievement is in itself a part of the liberation and a foundation for inner security. " --Albert Einstein