^^^
Yes, 650b is increasing in popularity in the U.S., especially in the West Coast. It's the new craze not only among MTBers, but also among other road groups, including hip city commuters converting older 700c bikes and long-distance riders with expensive custom bikes built in the French-style: low trail fork with pronounced offset, big front Berthoud bag, beautiful Honjo fenders, etc. 650b is still an underground movement among certain cycling groups, but that seems to be rapidly changing. If I'm not mistaken, Jan Heine and Grant Peterson are among two of the big proponents for 650b being used on road bikes in the U.S. There are already rumors that the bike industry has plans to standardize wheels to reduce costs in frame design, tire, rims, etc. 650b is the big focus. This remains to be seen!