bought a 29 – loved it. meanwhile my 26″ bike got more and more heavy duty (456 w/ pikes) every time i rode it it felt heavy and sluggish, i recently put on a normal stem and bars (70/ 685) and i’ve been riding it a bit more.
29 is good for longer rides & the 26 is fun for messing around in the woods.
just as mountain bikes haven’t replaced CX bikes and cruisers haven’t replaced 20″ bmx there will always be a place for both 26 & 29. that might not be in your shed, but some will want one, some the other & some will be “bikesexual”!