Originally Posted by veganbikes

You were doing so good.

26 is not almost extinct it is still very much used maybe not as much as it was but it is not near extinction or close to dead.
650B is not going anywhere it is an old French size that became quite popular again and will still be around a while. If it were dying I wouldn't be using it and I am using it on my mountain bike and my commuter and have plans for a gravel bike down the road that is 650b/27.5.
29 is fine no complaints not necessarily royalty of any gender but a fine size.

For instance QBP a very large distributor of bicycle parts lists 151 models of 27.5 tires (Not all MTB some have different sizes under those models) and under 29" you get 154 models (again with a bit of a mix and different sizes under that model) and for 26" you get 168 models (same thing as before with maybe a bit more road stuff maybe only because 27.5 and 29 usually is MTB specific where 26 is a bit more catch all) so I think if things were dying and extinct or on life support there wouldn't be nearly an equal number of each tire. If Schwalbe, Panaracer, Continental, Kenda and Cheng Shin (owners of Maxxis and they make some low quality stuff under CST) stop making 26" and 27.5/650B then yes we know things are on the way out. Right now not so much.