I have spent a lot of time lately cruising the BF archive and the web in general to learn about 650B wheels. I can totally understand the desire for a ballonish tire that will give a comfortable ride while carrying some weight and having the benefit of fenders. What I can't understand is what is the driving force to revive an old standard rather than modify an existing one. A 650B conversion (either of an 700c road bike or 26 mountain bike) is expensive. 650B wheels and tires are significantly more expensive, and options are fewer than 26" wheels and tires. They are insignificantly different sizewise, and should not provide any different ride qualities. I understand that the 26" tires are often made for rugged conditions and don't have the supple sidewalls desired by 650B enthusiasts. Why isn't the drive to get 26" tire manufacturers to make supple tires in 1.5 or 1.75 widths? Seems like it would be the path of far less resistance. And it would allow one to simply change tires and be able to go from wide knobbies for the trails, to narrower slicks for the road.
To extend the question, why are conversions often of 700c to 650B? Isn't converting a 26" mountain bike far easier?